Systems and methods for in-flight retrieval of unmanned aerial vehicles

ABSTRACT

Presently disclosed systems and methods are configured for in-flight retrieval of unmanned aerial vehicles (UAVs). Such systems generally include a retrieval ramp, a tether system including a tether, and a capture connector. The retrieval ramp is configured to be moved between a stowed configuration and an extended configuration, in which at least a portion of the retrieval ramp is positioned outside the aircraft for retrieval of the UAV. The tether system is moveable to a capture configuration, in which a terminal tether end of the tether is positioned beyond a terminal end of the retrieval ramp, typically outside of turbulence generated by the aircraft. The system is configured to position the retrieval ramp, the tether system, and the capture connector in order to engage the UAV with the capture connector. Once captured, the system may move the UAV into the aircraft as the tether is retracted towards a retracted configuration.

FIELD

The present disclosure relates to systems and methods for in-flightretrieval of unmanned aerial vehicles.

BACKGROUND

Unmanned aerial vehicles (UAVs), unmanned aircraft systems (UASs), orsimply “drones” are aircraft without a human pilot aboard. UAVs areutilized to perform various military, commercial, and residentialfunctions that may be difficult, dangerous, or too remote to beperformed using manned aircraft. Typically, one or more UAVs arelaunched from a ground-based launch point, and then recovered (alsoreferred to as “retrieved”) back to the launch point after performingtheir intended function. Retrieval of the UAV may allow for the UAV tobe refueled, rearmed, and/or potentially redeployed for the same or alater mission. UAVs typically are launched from the ground, from ships,or from aircraft. Often, UAVs are launched from a location close to themission location, which may endanger any ground forces or operators atthe launch point. The retrieval location may be the same as the launchpoint, close to the launch point, or remote from the launch point.Having a fixed retrieval location limits the range and effectiveness ofthe UAV, because the UAV must reserve fuel to return to the retrievallocation. Attempts at developing a system that provides for mobileretrieval locations for UAV capture (e.g., using a carrier aircraft, or“mother” aircraft) have met with difficulties, due to, for example,turbulence near the carrier aircraft, slow retrieval processes, and/orlimited capabilities (e.g., only capable of retrieving a single UAV).

SUMMARY

Presently disclosed systems and related methods for in-flight retrievalof one or more unmanned aerial vehicles (UAVs) may address one or moreissues existing in the prior art. One example of a presently disclosedsystem for retrieving an airborne UAV (e.g., capturing the airborne UAV,transferring it to an aircraft, and loading the UAV into the aircraft)while the aircraft is airborne generally includes a retrieval ramp, atether system, and a capture connector. The retrieval ramp has anelongate surface extending from a first end of the retrieval ramp to aterminal end of the retrieval ramp, and the retrieval ramp is configuredto be selectively and reversibly moved between a stowed configurationand an extended configuration. In the stowed configuration, theretrieval ramp is contained within the aircraft, and in the extendedconfiguration, at least the terminal end of the retrieval ramp ispositioned outside of the aircraft and turbulence generated by theaircraft (e.g., below the turbulence, or otherwise positioned to avoidthe turbulence), for capture of the UAV. The tether system has a tetherextending from an initial tether end to a terminal tether end, and thetether system is selectively and reversibly moveable between a retractedconfiguration, in which the terminal tether end is positioned inside theaircraft, and a capture configuration, in which the terminal tether endis positioned outside the aircraft, beyond the terminal end of theretrieval ramp (e.g., the terminal tether end may also be positioned ina location which is a safe distance from the aircraft and outside theturbulence generated by the aircraft).

The capture connector is coupled to the terminal tether end of thetether and is configured to engage the UAV outside of any turbulencegenerated by the aircraft. The system is configured to position theretrieval ramp, the tether system, and the capture connector in order tocapture the UAV, by engaging the UAV with the capture connector. Oncecaptured, the system is configured to move the UAV into the aircraft,utilizing the retrieval ramp, as the tether is retracted towards theretracted configuration.

Related methods may include approaching the UAV with the aircraft,lowering the retrieval ramp from the aircraft towards the extendedconfiguration, and extending a tether of the tether system towards acapture configuration, wherein, in the capture configuration, thecapture connector at the terminal tether end of the tether is positionedbeyond a terminal end of the retrieval ramp such that the tether isconfigured to capture the UAV outside of turbulence generated by theaircraft. Such methods may also include measuring relative locations andvelocities of the aircraft and the UAV, positioning the aircraft basedon the measured relative locations and velocities, capturing the UAV byengaging the capture connector with a UAV connector coupled to the UAV,and moving the UAV into the aircraft via the tether and the retrievalramp.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of illustrative, non-exclusive examples ofsystems for capturing a UAV and loading the UAV into an aircraft whilethe aircraft is airborne, according to the present disclosure.

FIG. 2 is a perspective cutaway view of an aircraft containing anexample of a system according to the present disclosure, with the cargobay closed and the system contained within the aircraft.

FIG. 3 is a perspective view of an example of a system according to thepresent disclosure, with the cargo bay open, the retrieval ramp in anextended configuration, and the tether in a capture configuration,illustrating capture of a UAV while the system is in a retrievalconfiguration.

FIG. 4 is a perspective view of a UAV being pulled into a restraintstructure of the retrieval ramp via retracting the tether after engagingthe tether with the UAV.

FIG. 5 is a perspective view of a system according to the presentdisclosure, with the system in a receiving configuration, showing theUAV in process of being loaded into the aircraft.

FIG. 6 is a perspective view of an example of a system according to thepresent disclosure, with the captured UAV positioned at least partiallywithin the aircraft and a drogue-receiver of the tether system being ina transfer configuration.

FIG. 7 is a perspective view of an example of a system according to thepresent disclosure, with the drogue-receiver of the tether system beingin a delivery configuration.

FIG. 8 is a perspective view of an example of a system according to thepresent disclosure, with a captured UAV being transferred to a storagestructure in the aircraft.

FIG. 9 is a perspective view of an example of a system according to thepresent disclosure, with the system being re-positioned in a retrievalconfiguration for capture of a second UAV.

FIG. 10 is a schematic flow chart diagram, representing methodsaccording to the present disclosure.

DESCRIPTION

As schematically illustrated in FIG. 1, systems 10 of the presentdisclosure are configured for capturing one or more UAVs 12 and loadingeach UAV 12 captured by a system 10 to an aircraft 14. Systems 10 areconfigured to capture a respective UAV 12 and transfer it to aircraft 14while UAV 12 and aircraft 14 are airborne. As used herein, a respectiveUAV 12 is “captured” when it is engaged with, coupled to, and/or atleast partially restrained by system 10. A respective UAV 12 is “loaded”within aircraft 14 when the UAV has been placed inside aircraft 14 bysystem 10. Systems 10 may include aircraft 14, one or more airborne UAVs12 (which are also referred to herein as simply UAVs 12, or as UAV 12),and/or a controller 16. Some systems 10 may be at least partiallycontained within aircraft 14. To retrieve UAV 12 while airborne (e.g.,capture UAV 12 and transfer UAV 12 to aircraft 14), systems 10 include aretrieval ramp 18 and a tether system 20. Generally, at least a portionof retrieval ramp 18 may be moved (e.g., lowered) towards an extendedconfiguration such that it is positioned outside of aircraft 14 (e.g.,in the airstream behind aircraft 14), and a tether 22 of tether system20 may be extended towards a capture configuration in order to captureUAV 12. After UAV 12 is captured, tether 22 may be retracted towards aretracted configuration to draw UAV 12 into aircraft 14. As designatedherein, UAVs are generally designated as UAV 12, while a respective UAV12 that is airborne may be designated as an airborne UAV 11, arespective UAV 12 that has been captured may be designated as a capturedUAV 13, and a respective UAV 12 that has been captured, loaded, andstored within aircraft 14 may be designated as a stored UAV 104,however, the respective UAV 12 is the same respective UAV 12 whether itis airborne, captured, or stored. Generally, in the figures, elementsthat are likely to be included in a given example are illustrated insolid lines, while elements that are optional to a given example areillustrated in broken lines. However, elements that are illustrated insolid lines are not essential to all examples of the present disclosure,and an element shown in solid lines may be omitted from a particularexample without departing from the scope of the present disclosure.

Retrieval ramp 18 is configured to be selectively and reversibly movedbetween a stowed configuration in which retrieval ramp 18 is containedwithin aircraft 14, and the extended configuration. For example, anelongate surface 24 of retrieval ramp 18 may be selectively andreversibly moveable with respect to aircraft 14 in order to moveretrieval ramp 18 between the stowed and extended configurations. Insome examples, elongate surface 24 of retrieval ramp 18 may extend froma first end 26 to a terminal end 28, wherein first end 26 remainspositioned inside aircraft 14, and terminal end 28 is positioned outsideof aircraft 14 when retrieval ramp 18 is in the extended configuration.Retrieval ramp 18 is configured to be deployed to a plurality ofdifferent positions with respect to aircraft 14 when extended towardsthe extended configuration. For example, retrieval ramp 18 may beconfigured to be deployed to a plurality of different distances andpositions relative to aircraft 14, such that the position of terminalend 28 relative to aircraft 14 is adjustable, such as to avoidturbulence produced by aircraft 14.

Additionally or alternatively, elongate surface 24 of retrieval ramp 18may include a first ramp portion 30 and a second ramp portion 32. Insuch examples, first ramp portion 30 may extend from first end 26 ofelongate surface 24 to a second end 34 of first ramp portion 30, andsecond ramp portion 32 may extend from a proximal end 36 of second rampportion 32 to terminal end 28 of elongate surface 24. First ramp portion30 and second ramp portion 32 may be coupled to one another adjacentsecond end 34 of first ramp portion 30 and proximal end 36 of secondramp portion 32. Second ramp portion 32 and first ramp portion 30 may berotationally disposed with respect to one another such that a ramp angle38 (FIG. 9) formed between first ramp portion 30 and second ramp portion32 is adjustable as second ramp portion 32 is rotated with respect tofirst ramp portion 30. For example, retrieval ramp 18 may include ahinge 40 coupled to first ramp portion 30 adjacent second end 34 offirst ramp portion 30, and to second ramp portion 32 adjacent proximalend 36 of second ramp portion 32, thereby hinging first ramp portion 30and second ramp portion 32 with respect to one another. In some suchsystems 10, retrieval ramp 18 may include a ramp adjustment mechanism 42configured to adjust ramp angle 38 between first ramp portion 30 andsecond ramp portion 32. For example, ramp adjustment mechanism 42 may beconfigured to rotate second ramp portion 32 with respect to first rampportion 30, thereby adjusting the position of terminal end 28 ofelongate surface 24 of retrieval ramp 18. As retrieval ramp 18 is movedtowards the extended configuration, at least a portion of second rampportion 32 may be positioned outside of aircraft 14 (e.g., rampadjustment mechanism 42 may be configured to extend at least a portionof retrieval ramp 18 into the airstream behind aircraft 14).

Retrieval ramp 18 may be configured such that there is at least a 45degree range of rotation, at least a 60 degree range of rotation, atleast a 90 degree range of rotation, at least a 120 degree range ofrotation, at least a 150 degree range of rotation, and/or at least a 180degree range of rotation of second ramp portion 32 with respect to firstramp portion 30. Ramp angle 38 (FIG. 9) is defined as 0 degrees (0°)when first ramp portion 30 and second ramp portion 32 are parallel witheach other. In the stowed configuration of retrieval ramp 18, ramp angle38 (FIG. 9) may be a positive angle, and/or, in the extendedconfiguration, ramp angle 38 (FIG. 9) may be a negative angle. Forexample, in the extended configuration shown in FIG. 9, retrieval ramp18 has a negative ramp angle 38′ that is negative in value, measuredfrom a ramp angle of 0° as indicated by dashed line 44. Dashed line 46indicates a positive ramp angle 38″ having a positive value, such as maybe the case when retrieval ramp 18 is in the stowed configuration andsecond ramp portion 32 is rotated up into aircraft 14. Ramp adjustmentmechanism 42 may be configured to position retrieval ramp 18 such thatany desired ramp angle 38 within the range of rotation may be formedbetween second ramp portion 32 and first ramp portion 30. For example,ramp adjustment mechanism 42 may be configured to position at least aportion of retrieval ramp 18 outside of aircraft 14 as retrieval ramp 18is moved towards the extended configuration, and to move retrieval ramp18 into aircraft 14 as retrieval ramp 18 is moved towards the stowedconfiguration. In some systems 10, at least a portion of retrieval ramp18 may be telescoping such that it extends in length in addition to orinstead of changing angle with respect to aircraft 14.

Returning now to FIG. 1, retrieval ramp 18 includes a restraintstructure 48 configured to at least partially secure a captured UAV(e.g., captured UAV 13, of FIG. 3) with respect to elongate surface 24of retrieval ramp 18 (e.g., with respect to second ramp portion 32).Restraint structure 48 may be configured to be selectively andreversibly moved with respect to elongate surface 24 of retrieval ramp18 (e.g., fore and aft with respect to elongate surface 24). Forexample, restraint structure 48 may be configured to be selectively andreversibly moved with respect to first ramp portion 30 (e.g., fore andaft with respect to first ramp portion 30) and with respect to secondramp portion 32 of retrieval ramp 18 (e.g., fore and aft with respect tosecond ramp portion 32). In some systems 10, restraint structure 48 maybe configured to slide from first ramp portion 30 to second ramp portion32. In some systems 10, at least a portion of restraint structure 48 mayextend past elongate surface 24 (e.g., past terminal end 28 of elongatesurface 24) when retrieval ramp 18 is in the extended configuration andrestraint structure 48 is positioned for capture of a respective UAV.

Restraint structure 48 may be configured to at least partially restraina respective UAV 12 once the respective UAV is secured within restraintstructure 48, such as while the respective UAV is moved throughturbulence generated by aircraft 14 (e.g., turbulent air 50 shown inFIG. 3) and/or as the respective UAV is moved into aircraft 14. Forexample, restraint structure 48 may be configured to at leastsubstantially prevent lateral movement of the captured UAV with respectto elongate surface 24 of retrieval ramp 18 (e.g., with respect to firstramp portion 30 and second ramp portion 32), once the captured UAV issecured within restraint structure 48. Restraint structure 48 may beconfigured to secure the captured UAV in at least 1 degree of freedom,at least 2 degrees of freedom, at least 3 degrees of freedom, at least 4degrees of freedom, at least 5 degrees of freedom, and/or at least 6degrees of freedom, with respect to elongate surface 24 of retrievalramp 18. In some systems 10, restraint structure 48 at least partiallyencloses the captured UAV, as it is moved into aircraft 14. Retrievalramp 18 may include a restraint transport mechanism 52 that isconfigured to move restraint structure 48 with respect to elongatesurface 24 of retrieval ramp 18 (e.g., with respect to first rampportion 30 and second ramp portion 32) and/or with respect to aircraft14. Thus, restraint transport mechanism 52 may move restraint structure48 along retrieval ramp 18 to position restraint structure 48 forreceiving a captured UAV 13, and restraint transport mechanism 52 mayagain move restraint structure 48 and the captured UAV containedtherein, with respect to retrieval ramp 18, after the captured UAV issecured within restraint structure 48, thereby moving the captured UAVtowards and into aircraft 14.

Tether system 20 is configured to be used with retrieval ramp 18 tocapture UAV 12 and transfer UAV 12 to aircraft 14. Tether 22 extendsfrom an initial tether end 54 to a terminal tether end 56. Generally,initial tether end 54 remains coupled to system 10 and positioned withinaircraft 14, while terminal tether end 56 is extended out of aircraft 14as tether system 20 is moved towards the capture configuration tocapture an airborne UAV 11. Tether system 20 is selectively andreversibly moveable between the retracted configuration, in whichterminal tether end 56 may be positioned inside aircraft 14, and thecapture configuration, in which terminal tether end 56 is positionedoutside aircraft 14 in a position suitable for capturing UAV 12.

Tether 22 has a length (e.g., the distance between initial tether end 54and terminal tether end 56) sufficient for capturing and transferringUAV 12 to aircraft 14. Tether system 20 also includes a captureconnector 58 disposed at or near terminal tether end 56 of tether 22.Capture connector 58 is configured to engage UAV 12, thereby capturingit such that as tether system 20 is retracted towards the retractedconfiguration and terminal tether end 56 is pulled in towards aircraft14, UAV 12 is pulled along with tether 22 and capture connector 58. Forexample, UAV 12 includes a UAV connector 60 configured to be engagedwith capture connector 58 of tether system 20, such that UAV 12 iscaptured by system 10 when UAV connector 60 and capture connector 58 areengaged with one another. In some examples, tether 22 may be configuredto grasp or otherwise be coupled to UAV 12 without a UAV connector 60present on a given UAV 12.

Tether system 20 is generally arranged with respect to retrieval ramp 18such that a portion of tether 22 is disposed within or through restraintstructure 48 of retrieval ramp 18 when tether system 20 is extendedtowards the capture configuration. In such a configuration, terminaltether end 56 and capture connector 58 may be positioned beyond terminalend 28 of retrieval ramp 18 (e.g., a portion of tether 22 may extendbeyond elongate surface 24 of retrieval ramp 18). As used herein, theterm “beyond” refers to a position more distant from the aircraft. Thus,terminal tether end 56 of tether 22 is positioned “beyond” terminal end28 of retrieval ramp 18 when terminal tether end 56 is farther fromaircraft 14 than is terminal end 28 of retrieval ramp 18.

A drogue 62 may be coupled to terminal tether end 56 of tether 22 suchthat drogue 62 may be configured to receive at least a portion of UAV 12as the UAV is captured. For example, drogue 62 may be shaped to receivea nose portion 64 and/or a probe 66 of UAV 12, such that once UAV 12 iscaptured by system 10, nose portion 64 and/or probe 66 is positioned atleast partially within drogue 62 of system 10 (e.g., nose portion 64and/or probe 66 of UAV 12 may be configured to be inserted into drogue62 as UAV 12 is captured). In some examples, drogue 62 may besubstantially funnel-shaped. Capture connector 58 may be disposed withindrogue 62. In other systems 10, any suitable structure may be coupled toterminal tether end 56 in place of drogue 62, or tether 22 may simplyend at capture connector 58 without an additional structure.

Tether system 20 may include a tether extension mechanism 68 configuredto selectively and reversibly extend tether 22 towards the captureconfiguration and retract tether 22 towards the retracted configuration.For example, tether extension mechanism 68 may include a spool, a reel,a winch, a pulley, and/or a retractable cord reel. Tether 22 may includea stowed portion 70 that is stowed about or within tether extensionmechanism 68, and an extended portion 72 that is not stowed about orwithin tether extension mechanism 68. For example, stowed portion 70 maybe the respective portion of tether 22 that is wrapped or wound around areel (e.g., tether extension mechanism 68), while extended portion 72may be the respective portion of tether 22 that is not wrapped or woundaround the reel, and therefore extends away from the reel. Generally,stowed portion 70 includes initial tether end 54 such that initialtether end 54 is engaged with tether extension mechanism 68. Extendedportion 72 may extend away from tether extension mechanism 68, such astowards a frame 74 that may link components of system 10 together.

In some examples, in the retracted configuration, a respective length ofstowed portion 70 is greater than a respective length of extendedportion 72 (e.g., because a majority of tether 22 may be stowed abouttether extension mechanism 68 in the retracted configuration). Bycontrast, in the capture configuration, a respective length of extendedportion 72 may be greater than a respective length of stowed portion 70(e.g., because a majority of tether 22 may be unwound from tetherextension mechanism 68 and extended out of aircraft 14). Similarly, arespective length of stowed portion 70 in the retracted configuration isgenerally greater than a respective length of stowed portion 70 in thecapture configuration, and a respective length of extended portion 72 inthe capture configuration is generally greater than a respective lengthof extended portion 72 in the retracted configuration. In other words,stowed portion 70 and extended portion 72 are not static lengths orportions of tether 22, and the relative portion of tether 22 that isstowed or extended may change as the tether system 20 is moved betweenthe retracted configuration and the capture configuration. Generally,stowed portion 70 is positioned within aircraft 14, such as within acargo bay 76 of aircraft 14. On the other hand, at least a portion ofextended portion 72 may be positioned outside aircraft 14. In someconfigurations, a portion of extended portion 72 may be positionedwithin cargo bay 76, and a portion of extended portion 72 may bepositioned outside aircraft 14.

Tether 22 may be any suitable material, but in some examples may be anelongate, flexible cable. Tether 22 may be constructed of any materialhaving suitable strength, weight and flexibility characteristics. Forexample, tether 22 may comprise woven fibers, KEVLAR®, one or moremetals, such as steel, alloys, and/or one or more polymers, such asnylon. In some examples, existing tethers may be adapted for use withpresently disclosed systems 10. For example, aerial refueling hoses maybe adapted to serve as a tether 22 in presently disclosed systems 10.The flexibility of tether 22 may be configured such that forces actingon either aircraft 14 or UAV 12 are not transferred through tether 22(e.g., forces acting on either aircraft 14 or the UAV 12 may be absorbedby tether 22 as it flexes).

Systems 10 may include frame 74 positioned within aircraft 14. In somesystems, frame 74 may be coupled to aircraft 14 such that frame 74 issubstantially immovable with respect to aircraft 14. Additionally oralternatively, frame 74 may be installed non-permanently such that it isselectively and reversibly removable from aircraft 14 and/or selectivelymoveable with respect to aircraft 14. Frame 74 may link one or morecomponents of system 10 to one another. For example, retrieval ramp 18and tether system 20 may be coupled to frame 74. In some examples, firstramp portion 30 of elongate surface 24 of retrieval ramp 18 may becoupled to frame 74 such that frame 74 supports first ramp portion 30.In some systems 10, frame 74 may be integrally formed with at least aportion of retrieval ramp 18 such that retrieval ramp 18 may includeframe 74. Additionally or alternatively, ramp adjustment mechanism 42may be coupled to frame 74, such that frame 74 supports ramp adjustmentmechanism 42. Additionally or alternatively, frame 74 may be configuredto guide and position tether 22 extending from within aircraft 14 (e.g.,extended portion 72 of tether 22), thereby facilitating positioning ofterminal tether end 56 beyond elongate surface 24 (e.g., beyond terminalend 28 of retrieval ramp 18) and beyond restraint structure 48. Forexample, terminal tether end 56 of tether 22 may extend away from tetherextension mechanism 68 and be guided by frame 74 such that extendedportion 72 of tether 22 extends along retrieval ramp 18 and throughrestraint structure 48. In some systems 10, extended portion 72 oftether 22 extends from tether extension mechanism 68, towards frame 74,and passes through a tether guide 77 coupled to the frame.

Additionally or alternatively, frame 74 may be configured to mount avision system 78 and/or one or more aircraft-based sensors 80. Visionsystem 78 and/or aircraft-based sensors 80 may be movable in somesystems 10. In some systems 10, frame 74 may be configured to aim and/orposition vision system 78 such that its field of regard (e.g., the totalarea that can be captured by vision system 78) is sufficient tofacilitate the capture of a UAV 12. For example, frame 74 may have aminimum height in order to facilitate such field of regard. Frame 74also may be configured to aim and/or position various system componentssuch that the respective components do not interfere with one another.For example, frame 74 may guide tether 22 such that the respectiveportion of tether 22 within aircraft 14 is held above and out of the wayof other system components, such as a storage structure 82 for storingretrieved UAVs and first ramp portion 30 of retrieval ramp 18. In thismanner, frame 74 may be configured to prevent tether 22 from interferingwith transfer of a captured UAV to storage structure 82. Frame 74 may bepositioned adjacent an aircraft door 84 that provides access to a cargobay 76 of aircraft 14.

Aircraft 14 may be any suitable aircraft. In some examples, aircraft 14may be a carrier aircraft or a cargo aircraft. Aircraft 14 may bespecifically designed and built for UAV launch and/or retrieval in someexamples. In other examples, aircraft 14 may be a converted aircraft,such as a cargo airlifter that has been converted to house system 10 forretrieval of airborne UAVs. Aircraft 14 may be piloted, autonomous,and/or remotely piloted in various examples. Retrieval ramp 18, tethersystem 20, and/or controller 16 may be housed inside aircraft 14.Additionally or alternatively, aircraft 14 may include one or moreaircraft-based sensors 80 configured to facilitate retrieval of UAV 12,frame 74, and/or one or more stored UAVs 104 that have previously beencaptured. For example, one or more system components may be housedwithin (e.g., positioned within and/or coupled to) cargo bay 76 ofaircraft 14. In some such examples, as retrieval ramp 18 is movedtowards the extended configuration, at least a portion of retrieval ramp18 (e.g., second ramp portion 32) may be moved out of cargo bay 76. Atleast a portion of retrieval ramp 18 may be mounted in cargo bay 76. Forexample, first ramp portion 30 may be mounted in cargo bay 76.Additionally or alternatively, one or more system components may becoupled to the exterior of aircraft 14. For example, one or moreaircraft-based sensors 80 may be mounted on or coupled to the exteriorof the aircraft in some examples.

UAV 12 may be any suitable UAV that generally includes one or more UAVconnectors 58, one or more probes 66, and/or a nose portion 64. Probe 66may be configured to send and/or receive wireless data, such asregarding location and velocity of the UAV and/or aircraft 14. UAV 12may be a fixed-wing UAV or may have one or more foldable wings. In somesystems 10, UAV 12 may be a rotorcraft, a quadcopter, an atmosphericre-entry vehicle, or any other unmanned aerial vehicle. UAV 12 mayinclude one or more UAV sensors 86 configured to facilitate retrieval ofthe UAV. UAVs 12 may be controlled remotely by an operator located onthe ground, in aircraft 14, or in another vehicle or aircraft, or UAV 12may be fully autonomous. UAV 12 may be configured for any type of taskor mission, and/or for recreational use. For example, UAV 12 may beconfigured to perform one or more of the following types of tasks beforebeing captured by system 10: target and decoy, reconnaissance, combat,logistics/cargo operations, research and development, civil andcommercial applications, military, aerial surveying (e.g., crops),acrobatic aerial footage in filmmaking, search and rescue, inspectingpower lines and pipelines, counting wildlife, delivering medical orother supplies to remote or inaccessible areas, environment monitoring,border patrol, convoy protection, forest fire detection, surveillance,coordinating humanitarian aid, plume tracking, land surveying, fire andaccident investigation, detection of illegal activities (e.g., hunting;landfill activities), landslide measurement, crowd monitoring, traffic,recreation, and construction industry tasks. UAV 12 may be configuredfor varying ranges and altitudes of flight, as desired.

Some systems 10 may include one or more additional features and/orcomponents as desired in individual applications. For example, restraintstructure 48 may include one or more friction-reducing structures 88configured to reduce friction between at least a portion of restraintstructure 48 and a UAV 12 captured by system 10, as UAV 12 is drawn intorestraint structure 48 (e.g., positioned at least partially withinrestraint structure 48). For example, friction-reducing structures 88may be provided in the form of one or more rollers 90, where each roller90 is configured to rotate about its respective longitudinal axis. Insome systems 10, one or more rollers 90 coupled to restraint structure48 are configured to rotate about their respective longitudinal axeswhen contacted by a captured UAV 13, as UAV is pulled into restraintstructure 48 and is moved with respect to the rollers 90. In thismanner, rollers 90 may reduce friction between UAV 12 and restraintstructure 48. Additionally or alternatively, one or morefriction-reducing structures 88 may be configured to guide UAV 12 intorestraint structure 48. As such, one or more friction-reducingstructures 88 may be positioned within an aft end 92 region of restraintstructure 48, where a captured UAV enters restraint structure 48.

Restraint structure 48 may take any suitable shape or form. In somesystems 10, restraint structure 48 may be configured to receive manydifferent types, sizes, and/or shapes of UAVs. In one specific example,restraint structure 48 may include a plurality of spaced-apart arches 94that are configured to receive a captured UAV. For example, eachspaced-apart arch 94 may connect opposing lateral end regions ofrestraint structure 48. In some examples, one or more friction-reducingstructures 88 may be positioned on and/or coupled to one or morerespective spaced-apart arches 94 of restraint structure 48.

Systems 10 may include one or more carriages 96 each configured tolongitudinally slide with respect to elongate surface 24 of retrievalramp 18 (e.g., with respect to first ramp portion 30 and/or second rampportion 32) and/or with respect to restraint structure 48. Eachrespective carriage 96 may thereby be configured to facilitate transferof a captured UAV into aircraft 14. For example, retrieval ramp 18 maybe configured such that as restraint structure 48 is moved with respectto elongate surface 24 of retrieval ramp 18, carriage 96 is moved withrespect to elongate surface 24 as well. In some systems 10, carriage 96may serve as a lower support for a captured UAV, such that the capturedUAV is positioned between carriage 96 and restraint structure 48. Somesystems 10 may include a plurality of carriages 96, such that there is arespective carriage 96 for each respective UAV the system is configuredto capture. Carriage 96 may slide along retrieval ramp 18 as thecaptured UAV is pulled into aircraft 14, and may travel with thecaptured UAV into aircraft 14, such as into a respective space ofstorage structure 82. In some such examples, each respective carriage 96may be stored in storage structure 82 until use. During use, therespective carriage 96 may be positioned on retrieval ramp 18 and movedalong with restraint structure 48 (with respect to elongate surface 24of retrieval ramp 18) to a position for capturing the next respectiveUAV 12. When positioned for capturing a respective airborne UAV 11, atleast a portion of carriage 96 may be positioned to extend beyondelongate surface 24 of retrieval ramp 18 and/or beyond aft end region 92of restraint structure 48.

Restraint structure 48 of some systems 10 may include a drogue-receiver98 within a fore end region 100 of the restraint structure (fore endregion 100 being opposite aft end region 92 of restraint structure 48).Said drogue-receiver 98 may be configured to engage drogue 62 of tethersystem 20. For example, as tether 22 and associated drogue 62 are drawninto aircraft 14 (e.g., as tether system 20 is moved towards theretracted configuration), drogue 62 may be pulled into drogue-receiver98 of restraint structure 48. In some examples, drogue-receiver 98 maybe configured to allow passage of tether 22 through an opening therein,but may simultaneously prevent passage of drogue 62 there through. Forexample, drogue-receiver 98 may have a complementary shape to that ofdrogue 62, such as being basket-like and/or substantially conical,thereby being configured to receive drogue 62, yet prevent its passagethrough drogue-receiver 98.

Drogue-receiver 98 may, in some examples, be coupled to or integrallyformed with a respective spaced-apart arch 94 of restraint structure 48.In some systems 10, drogue-receiver 98 may be configured to beselectively and reversibly moved between a transfer configuration and adelivery configuration. In the transfer configuration, drogue-receiver98 may be configured to prevent a captured UAV from being pulled offfore end region 100 of restraint structure 48 as the captured UAV istransferred into aircraft 14. In the delivery configuration,drogue-receiver 98 may be moved such that it is positioned such that thecaptured UAV may be transferred from restraint structure 48 to aircraft14, passing by fore end region 100 of restraint structure 48. Forexample, drogue-receiver 98 may be configured to rotate with respect torestraint structure 48 as drogue-receiver 98 is moved from the transferconfiguration to the delivery configuration. In this manner, once closeto or back within aircraft 14 after capturing UAV 12 outside of aircraft14, drogue-receiver 98 may be rotated with respect to restraintstructure 48 such that drogue-receiver 98 is moved out of the way toallow passage of the captured UAV. UAV 12 (e.g., captured UAV 13 shownin FIG. 3) may then be removed from restraint structure 48 and placedwithin aircraft 14, such as into storage structure 82. In otherexamples, drogue-receiver 98 may be transitioned to the deliveryconfiguration by mechanisms other than rotating with respect to the restof restraint structure 48. For example, drogue-receiver 98 may be slidto the delivery configuration, opened laterally to the deliveryconfiguration, moved vertically to the delivery configuration, expandedto the delivery configuration, and/or any other any other movement maybe performed to transition drogue-receiver 98 to the deliveryconfiguration to allow passage of the captured UAV. Alternatively, insome systems 10 without a drogue, drogue-receiver 98 may be replacedwith a different suitable structure to engage terminal tether end 56, ormay be absent altogether.

Systems 10 may include one or more storage structures 82 positionedwithin aircraft 14. Storage structure 82 is configured for receiving andstoring one or more UAVs 12 captured by system 10. Some storagestructures 82 include one or more storage cells 83 (or storage locations83), each of which serves as a space for a respective captured UAV.Respective storage cells 83 may be structurally separated from oneanother (such as by one or more side walls), or may simply be designatedspaces within storage structure 82 without a physical barrier betweenrespective storage cells 83. Each storage cell 83 may include arespective carriage 96. One or more storage cells 83 may contain astored UAV 104, which may be a respective airborne UAV 11 that has beencaptured by system 10. In some systems, storage structure 82 may beseparated from other components of the system (e.g., from frame 74) by adistance that is greater than or equal to the respective length of arespective captured UAV 13. In these systems 10, captured UAVs 13 may betransferred from retrieval ramp 18 to storage structure 82 after thecaptured UAV is brought into aircraft 14.

For example, in some systems, a transfer jack 102 may be included totransfer a captured UAV from retrieval ramp 18 and/or restraintstructure 48, into aircraft 14 (e.g., into storage structure 82contained within aircraft 14). Transfer jack 102 may be selectivelymoveable between a first position adjacent retrieval ramp 18, frame 74,and/or restraint structure 48, and a second position remote from thefirst position. For example, the second position may be adjacent storagestructure 82. A respective captured UAV may be placed onto transfer jack102 and moved away from retrieval ramp 18, restraint structure 48,and/or frame 74. Transfer jack 102 may then move (e.g., translate,raise, lower, tilt, and/or rotate) the captured UAV to another locationor position within aircraft 14, such as to or towards storage structure82.

Transfer jack 102 may be configured to selectively and reversibly raiseand lower a respective UAV 12 positioned on transfer jack 102, such thatonce a respective captured UAV has been transferred from retrieval ramp18 to storage rack 82 (or to another location within aircraft 14),transfer jack 102 may raise and/or lower the UAV to the desired positionor location. For example, transfer jack 102 may transfer a captured UAVaway from retrieval ramp 18, and deposit the captured UAV in storagestructure 82. In examples where storage structure 82 includes aplurality of storage cells 83 having different heights, transfer jack102 may raise or lower so as to deposit the captured UAV in the desiredrespective storage space, and/or so as to obtain a respective carriage96 from a respective storage space for retrieval of the next airborneUAV (e.g., airborne UAV 11′).

Controller 16 may generally include one or more sensors 106 (e.g., firstsensor 106, second sensor 106′, etc.) and one or more processors 108(e.g., first processor 108, second processor 108′, etc.). Sensors 106may be configured to measure the relative position and velocity betweencomponents of system 10. For example, first sensor 106 may be configuredto measure the relative position and velocity between aircraft 14 and arespective airborne UAV 11, while second sensor 106′ may be configuredto measure the relative position and velocity between UAV connector 60of the respective airborne UAV 11 and capture connector 58 of system 10.In some systems 10, controller 16 may include a single sensor configuredto measure both relative position and velocity between aircraft 14 andUAV 12 as well as between UAV connector 60 and capture connector 58.

Processors 108 may be configured to process data from one or moresensors 106. In one example, first processor 108 may be configured toprocess data from first sensor 106, and second processor 108′ may beconfigured to process data from second sensor 106′. In some examples,first processor 108 maybe configured to process data from both firstsensor 106 and second sensor 106′. Processors 108 are generallyconfigured to guide aircraft 14 and airborne UAV 11 to a given relativeposition and velocity to facilitate capture of the UAV, and/or to guideand engage a respective UAV connector 60 of a respective airborne UAV 11with capture connector 58, thereby capturing airborne UAV 11 (at whichpoint UAV 12 is designated captured UAV 13).

Controller 16 may be configured to selectively position retrieval ramp18 in the stowed configuration, the extended configuration, and anyposition or arrangement there between. For example, controller 16 may beconfigured to position retrieval ramp 18 in response to measuredrelative positions and velocities of aircraft 14 and airborne UAV 11.Similarly, controller 16 may be configured to position tether system 20in the retracted configuration, the capture configuration, and anyposition or arrangement there between, such as in response to measuredrelative positions and velocities of aircraft 14 and airborne UAV 11. Tothis end, controller 16 may be configured to control restraint transportmechanism 52 and/or tether extension mechanism 68 in some systems 10.

Controller 16 is autonomous in some systems 10. In some systems 10,controller 16 is semi-autonomous. Controller 16 may be wholly orpartially contained within aircraft 14 in some systems 10. In othersystems, controller 16, or a portion thereof, may be positioned remotelyfrom aircraft 14. As indicated in dashed lines in FIG. 1, respectivesensors 106 and processors 108 may be configured to transmit data and/orinstructions wirelessly between respective sensors 106 and processors108. Controller 16 may be configured to compensate for turbulencegenerated by and near aircraft 14. For example, controller 16 may beconfigured to position retrieval ramp 18, restraint structure 48,terminal tether end 56, and/or drogue 62 to avoid areas of turbulentair, such that capture of UAV 12 (e.g., engagement of UAV connector 60with capture connector 58) occurs in an area outside of (e.g., lowerthan, higher than, to one side or the other of, beyond, etc.) theturbulence.

Sensors 106 may be any suitable sensor. In some systems, one or moresensors 106 (e.g., first sensor 106) may include a GPS system.Additionally or alternatively, one or more sensors 106 (e.g., secondsensor 106′) may include a LIDAR system. Other suitable sensors mayinclude a radio frequency apparatus, a satellite guidance apparatus, avisual guidance system, and/or any other type of sensors. In somespecific systems 10, controller 16 is configured to generate and executeinstructions that, when executed, cause first processor 108 to generatenavigation control signals for directing airborne UAV 11 to a relativeposition and velocity based on sensor information received from firstsensor 106. Additionally or alternatively, controller 16 may beconfigured to generate and execute instructions that, when executed,cause second processor 108′ to generate navigation control signals fordirecting airborne UAV 11 to a relative position and velocity based onsensor information received from second sensor 106′ so that UAVconnector 60 and capture connector 58 are engaged with one another. Insome systems 10, controller 16 may include one or more end effectors 109(e.g., first end effector 109 and/or second end effector 109′), each ofwhich may receive data from one or more processors (e.g., from firstprocessor 108 and/or second processor 108′) and perform one or moretasks to cause and/or facilitate positioning of one or more systemcomponents for capture of UAV 12. In some systems 10, controller 16 maysend wireless signals for one or more system components to cause orfacilitate positioning for capture of UAV 12.

Systems 10 may be configured to be installed within and/or at leastpartially positioned within one or more different aircraft 14. In someexamples, systems 10 may be configured to be reversibly installed withina respective aircraft 14, selectively removed from said aircraft, andinstalled within a different respective aircraft. For example,components of systems 10 (e.g., retrieval ramp 18, tether system 20,controller 16, storage structure 82, frame 74, and/or transfer jack 102)may be modular and selectively removable as a system or individuallyfrom a given aircraft 14. In one specific example, system 10 may bepalletized, such that it may be slid into or out of a respective cargobay of an aircraft (e.g., cargo bay 76 of aircraft 14). Systems 10 maybe configured to be adapted to a plurality of configurations ofrespective aircraft (e.g., systems 10 may be configured for use within aplurality of different types and/or sizes of aircraft 14).

Systems 10 may be configured to retrieve a plurality of respectiveairborne UAVs (e.g., airborne UAV 11, airborne UAV 11′, airborne UAV11″, etc.). Generally, system 10 is configured to capture multiplerespective UAVs serially, such that the system is configured to beplaced in a receiving configuration to capture a first respective UAV,moved towards a retrieval configuration to transfer the first respectiveUAV to the aircraft, and then system 10 may be moved back towards thereceiving configuration to capture a second respective UAV, and so on.However, system 10 may be configured to capture more than one respectiveairborne UAV 11 at a time. In the receiving configuration, system 10 isconfigured to receive a respective captured UAV within the aircraft. Forexample, tether system 20 may be moved towards the retractedconfiguration, retrieval ramp 18 may be moved towards the stowedconfiguration, and/or drogue-receiver 98 may be moved towards thedelivery configuration as system 10 is moved towards the retrievalconfiguration. Similarly, in the retrieval configuration, system 10 isconfigured to capture an airborne UAV 11. Accordingly, tether system 20may be moved towards the capture configuration, retrieval ramp 18 may bemoved towards the extended configuration, and/or drogue-receiver 98 maybe moved towards the transfer configuration as system 10 is movedtowards the receiving configuration. In the receiving configurationand/or when not in use, system 10 may be configured to be containedwithin aircraft 14, such that a door 84 to cargo bay 76 may be closed,whereas in the retrieval configuration, portions of system 10 arepositioned outside of aircraft 14.

In some examples, system 10 may be configured to redeploy, or relaunch,one or more UAVs 12 captured by the system, and/or systems 10 may beconfigured to deploy or launch a respective UAV 12 regardless of whetherit was previously retrieved by system 10 or otherwise located insideaircraft 14. For example, a respective UAV 12 may be removed fromstorage structure 82, transferred out of aircraft 14 via tether system20 and retrieval ramp 18, and released into the airstream outside ofaircraft 14 by decoupling the UAV's UAV connector 60 from captureconnector 58 of system 10, thereby (re)deploying UAV 12. In(re)launching or (re)deploying a given UAV 12, system 10 may performfunctions in reverse order than when retrieving an airborne UAV. Whilesystems 10 and components described above are generally described withreference to capturing a respective UAV 12, it should be understood thatsaid systems 10 and components thereof may be configured to transferUAVs out of the aircraft in addition to or instead of transferring UAVsinto the aircraft. Additionally or alternatively, systems 10 may beconfigured to recharge, refuel, and/or reconfigure one or more capturedUAVs. To this end, aircraft 14 may contain components used in therefueling, rearming and/or servicing of UAV 12. For example, aircraft 14may contain fuel, armaments, spare parts, extra pilots, etc. Forextended missions, aircraft 14 may include sleeping quarters for pilotsand other personnel. Personnel aboard aircraft 14 may perform refueling,rearming and/or servicing of the UAV 12. In other examples, aircraft 14may include an autonomous refueling/rearming/servicing system, and maybe completely unmanned.

Turning now to FIGS. 2-9, illustrative non-exclusive examples of systems10 are illustrated, in the form of system 110 (which is an example ofsystem 10). Where appropriate, the reference numerals from the schematicillustrations of FIG. 1 are used to designate corresponding parts ofsystem 110; however, the examples of FIGS. 2-9 are non-exclusive and donot limit systems 10 to the illustrated embodiments of system 110. Thatis, systems 10 are not limited to the specific embodiments of theillustrated system 110, and systems 10 may incorporate any number of thevarious aspects, configurations, characteristics, properties, etc. ofsystems 10 that are illustrated in and discussed with reference to theschematic representations of FIG. 1 and/or the embodiments of FIGS. 2-9,as well as variations thereof, without requiring the inclusion of allsuch aspects, configurations, characteristics, properties, etc. For thepurpose of brevity, each previously discussed component, part, portion,aspect, region, etc. or variants thereof may not be discussed,illustrated, and/or labeled again with respect to system 110; however,it is within the scope of the present disclosure that the previouslydiscussed features, variants, etc. may be utilized with the same.

FIG. 2 illustrates a schematic view of system 110 in a stowedconfiguration. Aircraft 14 is shown with a cutaway view, so that therest of system 110 may be visible as positioned inside cargo bay 76 ofaircraft 14. As shown in FIG. 2, aircraft door 84 is closed, and thusthe system components (e.g., storage structure 82, tether system 20,frame 74, retrieval ramp 18, and restraint structure 48) are all whollycontained within cargo bay 76 of aircraft 18. As so positioned, tethersystem 20 is in its retracted configuration, retrieval ramp 18 is in itsstowed configuration, and drogue-receiver 98 is in its transferconfirmation. As shown in FIG. 2, second ramp portion 32 is tiltedupwards from first ramp portion 30 of retrieval ramp 18, such that rampangle 38 has a positive value. This configuration may be advantageousfor closure of aircraft door 84. Storage structure 82 as shown in FIG. 2includes a respective stored UAV 104 and a respective carriage 96 ineach respective storage cell 83. While storage structure 82 includeseight storage cells 83 (e.g., storage structure 82 accommodates eightstored UAVs 104), storage structure 82 may be configured to store moreor fewer stored UAVs 104 (e.g., storage structure 82 may include more orfewer storage cells 83 than illustrated in some examples). As shown inthe stowed configuration of FIG. 2, tether 22 is almost entirely wrappedaround a reel 112 (which is an example of tether extension mechanism68), such that the length of stowed portion 70 of tether 22 is muchgreater than the length of extended portion 72 of tether 22.

FIG. 3 illustrates system 110 of FIG. 2, having been moved to aretrieval configuration for capture of an airborne UAV 11 (shown ascaptured UAV 13). In contrast with the stowed configuration shown inFIG. 2, in FIG. 3, aircraft door 84 is open, retrieval ramp 18 has beenmoved towards the extended configuration, tether system 20 has beenmoved towards the capture configuration, and capture connector 58adjacent terminal tether end 56 of tether 22 has been engaged with UAVconnector 60 of UAV 12 to capture the UAV. As shown in FIG. 3, whencaptured, at least a portion of UAV 12 is positioned within drogue 62adjacent terminal tether end 56. Capture connector 58 is disposed withindrogue 62. Second ramp portion 32 has been rotated downwards withrespect to first ramp portion 30, such that ramp angle 38 has a negativevalue and second ramp portion 32 extends downward, out of aircraft 14.First ramp portion 30 remains within aircraft 14, secured to frame 74.Extended portion 72 of tether 22 has been unwound from reel 112 (shownin FIG. 2), and tether 22 passes through an opening 114 indrogue-receiver 98 of restraint structure 48 (opening 114 is best seenin FIG. 4), and then is disposed to pass through restraint structure 48as shown.

As positioned for capturing an airborne UAV 11 (shown as captured UAV 13in FIG. 3), carriage 96 is positioned such that at least a portion ofcarriage 96 extends beyond elongate surface 24 (e.g., beyond terminalend 28 of elongate surface 24) of retrieval ramp 18, and beyond aft endregion 92 of restraint structure 48. For example, a portion 116 ofcarriage 96 is positioned beyond aft end region 92 of restraintstructure 48 in FIG. 3. Substantially all of carriage 96 is positionedbeyond terminal end 28 of retrieval ramp 18. Additionally, frame 74 isconfigured to guide and position tether 22 extending from withinaircraft 14 (e.g., extended portion 72 of tether 22), therebyfacilitating positioning of terminal tether end 56 beyond elongatesurface 24 (e.g., beyond terminal end 28 of retrieval ramp 18) andbeyond aft end region 92 of restraint structure 48. Accordingly, drogue62 and capture connector 58 (each of which are situated adjacentterminal tether end 56 in system 110) are positioned beyond terminal end28 of retrieval ramp 18 and beyond aft end region 92 of restraintstructure 48, as shown.

FIG. 3 schematically illustrates an area of turbulence 50 (also referredto herein as turbulent air 50), generated by and adjacent aircraft 14.Such area of turbulence 50 is often generated by aircraft in areas ofthe airstream near aircraft 14 and/or behind aircraft 14 (relative tothe direction of travel of aircraft 14, indicated by arrow 118), asshown in FIG. 3. System 110 is configured to capture UAV 12 at a capturelocation 120 that is positioned outside area of turbulence 50 (e.g.,above, below, beyond, and/or to the side of the turbulence). Capturelocation 120 is the location in space where UAV 12 is captured (e.g.,where capture connector 58 of tether system 20 is engaged with UAVconnector 60 of UAV 12). Capturing UAV 12 outside area of turbulence 50may lessen difficulties of capture that may be caused by turbulent air50.

As shown in FIG. 3, terminal tether end 56 of tether 22, drogue 62, andcapture connector 58 are each positioned beyond area of turbulence 50 inthe illustrated receiving configuration of system 110. In some systems,terminal end 28 of retrieval ramp 18 also may be positioned below,beyond, or otherwise outside of area of turbulence 50, in its extendedconfiguration.

FIG. 4 illustrates a close-up view of a respective captured UAV 13 beingdrawn into restraint structure 48 of system 110, as tether system 20 istransitioned towards the retracted configuration. As compared with theconfiguration illustrated in FIG. 3, the length of extended portion 72of tether 22 has been reduced by tether extension mechanism 68 (FIG. 2)such that terminal tether end 56 is drawn closer to and back towardsaircraft 14. As terminal tether end 56 and drogue 62 are drawn intoaircraft 14 (such as by reeling in tether 22 and/or by adjusting theposition of restraint structure 48 relative to retrieval ramp 18, suchas via restraint transport mechanism 52 of FIG. 1), captured UAV 13 isdrawn into restraint structure 48 and onto carriage 96, as shown in FIG.4. As tether 22 is further retracted towards the retractedconfiguration, captured UAV 13 will be further drawn into restraintstructure 48 until drogue 62 is drawn into drogue-receiver 98 of tethersystem 20. Tether 22 passes through opening 114 in drogue-receiver 98,but drogue-receiver 98 is configured to prevent drogue 62 and capturedUAV 13 from being pulled or drawn entirely through restraint structure48, while drogue-receiver 98 is in the transfer configuration shown.

As best seen in FIG. 4, restraint structure 48 of system 110 includes aplurality of spaced-apart arches 94 configured to receive captured UAV13. Restraint structure 48 of system 110 includes three suchspaced-apart arches 94, but other examples may include more or fewerspaced-apart arches 94, or a different configuration altogether.Restraint structure 48 generally may take any suitable form such that itsufficiently restrains captured UAV 13 during capture and transfer ofthe UAV to aircraft 14. As shown in FIG. 4, spaced-apart arches 94connect opposing lateral end regions 122 of restraint structure 48 insome examples. Planes defined by spaced-apart arches 94 aresubstantially orthogonal to a longitudinal axis 124 of restraintstructure 48, in some examples. Drogue-receiver 98 is integrally formedwith one respective arch 94 of the spaced-apart arches 94 in someexamples. In other examples, drogue-receiver 98 may be coupled to arespective arch 94 of restraint structure 48, or otherwise coupled torestraint structure 48 adjacent fore end region 100 of restraintstructure 48.

Restraint structure 48 of system 110 includes a plurality offriction-reducing structures 88 in the form of a plurality of rollers90. Friction-reducing structures 88 generally are positioned within aftend region 92 of restraint structure 48 such that captured UAV 13contacts and engages friction-reducing structures 88 as it is pulledinto restraint structure 48. In system 110, captured UAV 13 contactsrollers 90 (which are coupled to a respective spaced-apart arch 94 insome examples) as the UAV enters restraint structure 48, thereby causingrollers 90 to rotate about each roller's respective longitudinal axis126, as indicated by arrow 128, thereby reducing friction betweencaptured UAV 13 and restraint structure 48. While rollers 90 are shownin system 110 of FIG. 4, other systems may include more, fewer, and/or adifferent arrangement of friction-reducing structures 88. While rollers90 are illustrated coupled to or adjacent the respective spaced-apartarch 94 nearest aft end region 92 of restraint structure 48, otherrespective spaced-apart arches 94 may include one or morefriction-reducing structures 88 in addition to or instead of theillustrated rollers 90.

FIG. 5 illustrates system 110 being further transitioned towards thereceiving configuration. In FIG. 5, as compared to the configurations ofFIGS. 3-4, retrieval ramp 18 has been raised and adjusted such thatsecond ramp portion 32 is almost parallel with first ramp portion 30,and tether system 20 has been further retracted towards the retractedconfiguration by winding tether 22 about reel 112. Accordingly, terminaltether end 56 is once again near aircraft 14, and as tether 22 isfurther retracted, restraint structure 48 and carriage 96 translatelongitudinally with respect to retrieval ramp 18, thereby bringingcaptured UAV 13 into aircraft 14.

As best seen in FIG. 5, frame 74 of system 110 includes tether guide 77,through which tether 22 passes as it extends from tether extensionmechanism 68 and out of aircraft 14. Frame 74 is configured to positiontether guide 77 above other system components, such that tether 22 doesnot interfere with storage structure 82, transfer jack 102, or retrievalramp 18 as system 110 is transitioned between the receiving andretrieval configurations. Frame 74 of system 110 also positions andsupports vision system 78, and frame 74 is configured to position visionsystem 78 such that a sufficient field of vision of the airstreamoutside aircraft 14 is viewable, in order to facilitate capture of UAV12.

Turning now to FIG. 6, system 110 has been further transitioned towardsthe receiving configuration, as compared to the configuration shown inFIG. 5. Compared to FIG. 5, retrieval ramp 18 has been further raisedsuch that second ramp portion 32 is substantially parallel with firstramp portion 30. Additionally, tether system 22 in FIG. 6 has beenfurther retracted towards the retracted configuration such that agreater proportion of tether 22 is stowed about reel 112, therebycausing captured UAV 13, restraint structure 48, and carriage 96 to betranslated with respect to elongate surface 24 of retrieval ramp 18,until captured UAV 13 is positioned at least partially within aircraft14. As shown in FIG. 6, in this configuration, restraint structure 48,carriage 96, and captured UAV 13 are partially positioned within frame74.

Next, as shown in FIG. 7, drogue-receiver 98 is transitioned to thedelivery configuration, wherein drogue-receiver 98 is rotated withrespect to the rest of restraint structure 48, thereby allowing passageof captured UAV 13 through the respective spaced-apart arch 94 nearestfore end region 92 of restraint structure 48. In transitioningdrogue-receiver 98 to the delivery configuration, UAV connector 60 ofcaptured UAV 13 is disengaged from capture connector 58 within drogue62, and probe 66 of captured UAV 13 is removed from drogue 62. Suchmovement of drogue-receiver 98 to the delivery configuration may beaccomplished by further retracting tether 22, as guided by tether guide77 on frame 74, thereby pulling drogue 62 and drogue-receiver 98 awayfrom captured UAV 13. In other examples, a separate mechanism may beconfigured to move drogue-receiver 98 to the delivery configuration.

FIG. 8 illustrates movement of captured UAV 13 and carriage 96 out ofrestraint structure 48 and off of retrieval ramp 18, onto transfer jack102. Transfer jack 102 is configured to transfer captured UAV 13 into arespective vacant storage cell 83′ of a plurality of storage cells 83 ofstorage structure 82. As shown in FIG. 8, storage structure 82 includesa plurality of stored UAVs 104 (which were previously captured by system110), each respective stored UAV 104 having a respective carriage 96 anda respective storage cell 83 within storage structure 82. Storagestructure 82 includes a top row 130 of storage cells 83, and a bottomrow 132 of storage cells 83, though other examples may include more orfewer rows and/or cells. Transfer jack 102 is configured to translate inthe X-Y direction to position captured UAV 13 with respect to vacantstorage cell 83′. Additionally, transfer jack 102 is configured to raiseand lower in the Z direction, such that it is configured to place thecaptured UAV 13 in any respective row (e.g., at varying heights) ofstorage structure 82.

FIG. 9 illustrates system 110 being once again transitioned towards theretrieval configuration, to retrieve another airborne UAV. As shown inFIG. 9, retrieval ramp 18 has been moved towards the extendedconfiguration by lowering at least a portion of the ramp out of aircraft14, restraint structure 48 and carriage 96 have been positioned at leastpartially beyond terminal end 28 of elongate surface 24 of retrievalramp 18, and terminal tether end 56 of tether 22 and drogue 62 have beenextended beyond aft end region 92 of restraint structure 48 in order tocapture the next UAV. Feedback from vision system 78, other onboardsensors, and/or from sensors on airborne UAV 11 (FIG. 1) may be used bycontroller 16 (FIG. 1) to adjust the positions of retrieval ramp 18,terminal tether end 56, and/or restraint structure 48 in order tocapture the airborne UAV.

FIG. 10 schematically provides a flowchart that represents illustrative,non-exclusive examples of methods 200 for retrieving a UAV (e.g., UAV12) into an aircraft (e.g., aircraft 14) while the UAV and aircraft areairborne, according to the present disclosure. In FIG. 10, some stepsare illustrated in dashed boxes indicating that such steps may beoptional or may correspond to an optional version of a method accordingto the present disclosure. That said, not all methods according to thepresent disclosure are required to include the steps illustrated insolid boxes. The methods and steps illustrated in FIG. 10 are notlimiting and other methods and steps are within the scope of the presentdisclosure, including methods having greater than or fewer than thenumber of steps illustrated, as understood from the discussions herein.

Methods 200 include approaching the UAV with the aircraft at 202,lowering a retrieval ramp (e.g., retrieval ramp 18) from the aircrafttowards an extended configuration at 204, and capturing the UAV byengaging a capture connector (e.g., capture connector 58) with a UAVconnector (e.g., UAV connector 58) coupled to the UAV at 206. Loweringthe retrieval ramp at 204 includes extending a tether (e.g., tether 22)towards a capture configuration and optionally may include adjusting aramp angle between portions of the retrieval ramp at 208 (e.g., rampangle 38 between first portion 30 and second portion 32 of retrievalramp 18). Lowering the retrieval ramp at 204 may include opening a cargobay door of the aircraft (e.g., aircraft door 84) in order to allow theretrieval ramp and tether to be moved (e.g., lowered) into the airstreambehind the aircraft. Extending the tether at 204 may include extendingthe tether until the capture connector at the terminal tether end of thetether is positioned beyond an area of turbulence (e.g., area ofturbulence 50) generated by the aircraft, such that the captureconnector may be engaged with the UAV connector of the airborne UAV(e.g., airborne UAV 11) outside the area of turbulence. Extending thetether at 204 may be performed using a tether extension mechanism (e.g.,tether extension mechanism 68), such as by reeling out the tether fromabout a reel or other device.

Once the airborne UAV is captured at 206, methods 200 include moving thecaptured UAV (e.g., captured UAV 13) into the aircraft via the tetherand retrieval ramp at 210. Moving the captured UAV into the aircraftgenerally includes retracting the tether to pull the captured UAV into arestraint structure (e.g., restraint structure 48) and onto a carriage(e.g., carriage 96) at 212, raising the retrieval ramp from the extendedconfiguration towards a stowed configuration and retracting the tethertowards a retracted configuration at 214, and transferring the carriageand restraint structure along the retrieval ramp towards the aircraft at216. Retracting the tether to pull the captured UAV into the restraintstructure at 212 may include securing the captured UAV in six degrees offreedom within the restraint structure, such that the restraintstructure is configured to prevent rotation and/or lateral movement ofthe captured UAV with respect to the retrieval ramp as the captured UAVis being transferred to the aircraft (e.g., as the captured UAV is movedlongitudinally along the retrieval ramp, towards the aircraft). In somemethods 200, raising the retrieval ramp and retracting the tether at 214also may include closing the cargo bay door of the aircraft, to containthe system within the aircraft. For example, once all desired airborneUAVs have been captured, the aircraft door may be closed and the systemmay be placed in a stowed configuration while not in active use.

Once the captured UAV has been loaded within the aircraft, the UAVconnector and capture connectors are disengaged from one another at 218,and a drogue-receiver (e.g., drogue-receiver 98) may be moved from atransfer configuration to a delivery configuration to allow transfer ofthe captured UAV out of the restraint structure and into the aircraft.For example, the captured UAV and carriage may be transferred onto atransfer jack (e.g., transfer jack 102) at 220 and/or the captured UAVand carriage may be transferred to a storage structure (e.g., storagestructure 82) within the aircraft at 222, such as via the transfer jack,via personnel onboard the aircraft, and/or via another device.

Once the captured UAV has been stored within the aircraft, the systemmay be redeployed to capture another respective airborne UAV (e.g.,airborne UAV 11′). In some methods 200, redeploying the system includestransferring a second respective carriage (e.g., a carriage stored inthe storage structure in a vacant storage cell) to the restraintstructure at 224, moving the drogue-receiver back to the transferconfiguration at 226 (e.g., by rotating the drogue-receiver with respectto the restraint structure), and again lowering the retrieval ramp andextending the tether at 204. Then a second airborne UAV may be capturedat 206 by engaging the capture connector with the respective UAVconnector of the second airborne UAV. The other method steps regardingmeasuring and positioning the system components, and transferring thesecond captured UAV into the aircraft may be performed again, and so on,until all desired airborne UAVs have been retrieved by the aircraft andsystems according to the present disclosure.

In some methods 200, the restraint structure and carriage may betransferred (e.g., moved) with respect to the retrieval ramp at 228 inorder to capture a UAV. Such movement of the restraint structure andcarriage may be performed before, after, or contemporaneously with thelowering of the retrieval ramp and extending the tether at 204.Translating the restraint structure and carriage along the retrievalramp at 228 may be performed until the restraint structure and carriageare positioned adjacent a terminal end of the retrieval ramp (e.g.,terminal end 28). Additionally or alternatively, translating therestraint structure and carriage with respect to the retrieval ramp at228 may be performed using a restraint transport mechanism (e.g.,restraint transport mechanism 52). In some methods, an initial carriageis transferred from the storage structure to the retrieval ramp at 230before lowering the retrieval ramp at 204, such as for capture of thefirst respective UAV in a given flight.

Methods 200 include measuring relative positions and velocities of theaircraft and the UAV, which may be performed before the initial approachat 202, at 232, and/or after the initial approach at 202 and thelowering the retrieval ramp at 204, at 234. Measuring relative positionsand velocities at 232 and 234 may also include processing such data andgenerating instructions for guiding and positioning the aircraft and UAVat 236, based on the measured relative positions and velocities.Measuring relative positions and velocities of the aircraft and UAV at232 and 234 may include measuring said positions and velocities with oneor more sensors positioned on the aircraft and UAV. In some methods 200,guiding and positioning the aircraft and UAV at 236 may includecompensating for turbulence adjacent to and generated by the aircraft.In some methods 200, measuring relative positions and velocities at 232may be performed using a first sensor, and measuring relative positionsand velocities at 234 may be performed using a second sensor. In somemethods, measuring the relative positions and velocities at 232 and/or234 may include measuring the relative positions and velocities of thecapture connector and the UAV connector of the UAV being captured.

In some methods 200, one or more UAVs may be launched from the aircraftat 238 and/or the airborne UAV may perform one or more missions at 240prior to being captured by the aircraft at 206. Launching one or moreUAVs from the aircraft at 238 may include refueling, recharging, and/orreconfiguring the UAV before launch. Launching the UAV at 238 may beperformed from a ground location, from a vessel positioned within a bodyof water, or may be performed from the aircraft while airborne.

In some methods 200, the system may be installed in an aircraft at 242prior to capturing one or more UAVs. Similarly, the system may beremoved from the aircraft at 244, such as after capturing one or moreUAVs. For example, systems according to the present disclosure may beconfigured to be palletized, such that they may be easily installed at242 and/or removed at 244, such that a given system may be used in avariety of different aircraft. One or more steps of methods 200 may beautomated, and/or one or more steps of methods 200 may be performed byan operator, who may be located on the aircraft, or may be locatedremotely from the aircraft.

Illustrative, non-exclusive examples of inventive subject matteraccording to the present disclosure are described in the followingenumerated paragraphs:

A1. A retrieval ramp configured to transfer a UAV to and/or from anaircraft while the UAV and the aircraft are airborne, wherein theretrieval ramp comprises an elongate surface, wherein the retrieval rampis configured to be selectively and reversibly moved between a stowedconfiguration in which the retrieval ramp is contained within theaircraft, and an extended configuration, in which at least a portion ofthe retrieval ramp is positioned outside of the aircraft.

A1.1. The retrieval ramp of paragraph A1, wherein the retrieval ramp isconfigured to capture the UAV and load the UAV into the aircraft whilethe aircraft is airborne.

A1.2. The retrieval ramp of paragraph A1 or A1.1 wherein the retrievalramp is configured to deliver the UAV from the aircraft and release theUAV while the aircraft is airborne.

A1.3. The retrieval ramp of any of paragraphs A1-A2, wherein theelongate surface of the retrieval ramp extends from a first end of theretrieval ramp to a terminal end of the retrieval ramp.

A1.4. The retrieval ramp of paragraph A1.3, wherein the elongate surfaceof the retrieval ramp comprises:

a first ramp portion positioned at least partially within the aircraft,the first ramp portion extending from the first end of the retrievalramp to a second end of the first ramp portion; and

a second ramp portion extending from a proximal end of the second rampportion to the terminal end of the retrieval ramp, wherein the secondramp portion is coupled to the first ramp portion adjacent the proximalend of the second ramp portion and the second end of the first rampportion.

A1.5. The retrieval ramp of any of paragraphs A1-A1.4, furthercomprising a frame positioned within the aircraft.

A1.6. The retrieval ramp of paragraph A1.5, wherein the retrieval rampis coupled to the frame.

A1.7. The retrieval ramp of paragraph A1.5 or A1.6, wherein a/the firstramp portion of the retrieval ramp is coupled to the frame.

A1.8. The retrieval ramp of any of paragraphs A1-A1.7, wherein, in theextended configuration, a/the terminal end of the retrieval ramp ispositioned outside of the aircraft.

A1.9. The retrieval ramp of any of paragraphs A1-A1.8, wherein theaircraft is generating turbulence in an airstream.

A1.10. The retrieval ramp of any of paragraphs A1-A1.9, wherein, in theextended configuration, a/the terminal end of the retrieval ramp ispositioned outside of turbulence generated by the aircraft.

A2. The retrieval ramp of any of paragraphs A1-A1.10, wherein a/thesecond ramp portion and a/the first ramp portion are hinged with respectto one another, such that a ramp angle formed between the first rampportion and the second ramp portion is adjustable.

A3. The retrieval ramp of any of paragraphs A1-A2, wherein a/the secondramp portion and a/the first ramp portion are rotationally disposed withrespect to one another, such that a/the ramp angle formed between thefirst ramp portion and the second ramp portion is adjustable, and suchthat the second ramp portion may be rotated with respect to the firstramp portion.

A4. The retrieval ramp of any of paragraphs A1-A3, wherein the retrievalramp comprises a ramp adjustment mechanism configured to adjust a/theramp angle between a/the first ramp portion and a/the second rampportion.

A5. The retrieval ramp of any of paragraphs A1-A4, wherein the retrievalramp comprises a/the ramp adjustment mechanism configured to rotatea/the second ramp portion with respect to a/the first ramp portion.

A6. The retrieval ramp of any of paragraphs A1-A5, wherein at least aportion of the retrieval ramp is telescoping.

A7. The retrieval ramp of any of paragraphs A-A6, wherein a/the rampadjustment mechanism is configured to allow at least a 45 degree rangeof rotation, at least a 60 degree range of rotation, at least a 90degree range of rotation, at least a 120 degree range of rotation, atleast a 150 degree range of rotation, and/or at least a 180 degree rangeof rotation of a/the second ramp portion with respect to a/the firstramp portion.

A8. The retrieval ramp of any of paragraphs A1-A7, wherein a/the rampadjustment mechanism is configured to selectively and reversibly movea/the second ramp portion with respect to a/the first ramp portion suchthat at least a portion of the second ramp portion is positioned outsideof the aircraft in the extended configuration.

A9. The retrieval ramp of any of paragraphs A1-A8, wherein, in thestowed configuration, a/the ramp angle between a/the second ramp portionand a/the first ramp portion is a positive angle, wherein, in theextended configuration, the ramp angle between the second ramp portionand the first ramp portion is a negative angle, and wherein the rampangle is defined as 0 degrees when the second ramp portion and the firstramp portion are parallel.

A10. The retrieval ramp of any of paragraphs A1-A9, wherein a/the rampadjustment mechanism is configured to position a/the second ramp portionsuch that it is substantially parallel with a/the first ramp portion.

A11. The retrieval ramp of any of paragraphs A1-A10, wherein a/the rampadjustment mechanism is configured to extend a/the second ramp portionout of a cargo bay of the aircraft.

A12. The retrieval ramp of any of paragraphs A1-A11, wherein a/the rampadjustment mechanism is configured to extend at least a portion of theretrieval ramp into an airstream behind the aircraft.

A13. The retrieval ramp of any of paragraphs A1-A12, wherein a/the rampadjustment mechanism is configured to position the retrieval ramp backinto the aircraft after positioning at least a portion of the retrievalramp outside of the aircraft.

A14. The retrieval ramp of any of paragraphs A1-A13, wherein at least aportion of the retrieval ramp is mounted in a/the cargo bay of theaircraft.

A15. The retrieval ramp of any of paragraphs A1-A14, wherein a/the firstramp portion is mounted in a/the cargo bay of the aircraft.

A16. The retrieval ramp of any of paragraphs A1-A15, further comprisinga restraint structure configured to at least partially secure the UAVwith respect to the elongate surface of the retrieval ramp.

A16.1. The retrieval ramp of paragraph A16, wherein the restraintstructure is configured to at least partially secure the UAV withrespect to a/the second ramp portion of the retrieval ramp.

A17. The retrieval ramp of paragraph A16 or A16.1, wherein the restraintstructure is configured to be selectively and reversibly moved withrespect to the elongate surface of the retrieval ramp.

A17.1. The retrieval ramp of any of paragraphs A16-A17, wherein therestraint structure is configured to be selectively and reversibly movedwith respect to a/the first ramp portion and a/the second ramp portionof the retrieval ramp.

A18. The retrieval ramp of any of paragraphs A16-A17.1, wherein therestraint structure is configured to move fore and aft with respect toa/the first ramp portion and/or with respect to a/the second rampportion.

A18.1. The retrieval ramp of any of paragraphs A16-A18, wherein therestraint structure is configured to move fore and aft with respect tothe elongate surface of the retrieval ramp.

A19. The retrieval ramp of any of paragraphs A16-A18.1, wherein therestraint structure is configured to selectively slide from a/the firstramp portion to a/the second ramp portion, and vice versa.

A20. The retrieval ramp of any of paragraphs A16-A19, wherein, in theextended configuration, at least a portion of the restraint structureextends past the elongate surface of the retrieval ramp.

A20.1. The retrieval ramp of any of paragraphs A16-A20, wherein, in theextended configuration, at least a portion of the restraint structureextends past a/the terminal end of the retrieval ramp.

A21. The retrieval ramp of any of paragraphs A16-A20.1, wherein therestraint structure is configured to at least partially restrain the UAVonce the UAV is secured within the restraint structure, while the UAV isbeing moved into or out of the aircraft.

A21.1. The retrieval ramp of any of paragraphs A16-A21, wherein therestraint structure is configured to at least partially restrain the UAVwhile the UAV and the restraint structure are moved through turbulencegenerated by the aircraft.

A22. The retrieval ramp of any of paragraphs A16-A21.1, wherein therestraint structure is configured to prevent lateral movement of the UAVwith respect to the elongate surface of the retrieval ramp, while theUAV is secured within the restraint structure.

A22.1. The retrieval ramp of any of paragraphs A16-A22, wherein therestraint structure is configured to prevent lateral movement of the UAVwith respect to a/the first ramp portion and/or a/the second rampportion.

A23. The retrieval ramp of any of paragraphs A16-A22.1, wherein therestraint structure is configured to at least partially enclose the UAV,while the UAV is being moved into or out of the aircraft.

A24. The retrieval ramp of any of paragraphs A16-A23, wherein therestraint structure is configured to secure the UAV in at least 1 degreeof freedom, at least 2 degrees of freedom, at least 3 degrees offreedom, at least 4 degrees of freedom, at least 5 degrees of freedom,and/or at least 6 degrees of freedom.

A25. The retrieval ramp of any of paragraphs A16-A24, further comprisinga restraint transport mechanism configured to move the restraintstructure with respect to the aircraft.

A26. The retrieval ramp of paragraph A25, wherein the restrainttransport mechanism is configured to move the restraint structure withrespect to the elongate surface of the retrieval ramp.

A26.1. The retrieval ramp of paragraph A25, wherein the restrainttransport mechanism is configured to move the restraint structure withrespect to a/the first ramp portion and/or a/the second ramp portion.

A27. The retrieval ramp of any of paragraphs A1-A26.1, wherein theretrieval ramp is configured such that, in the extended configuration,a/the terminal end of the retrieval ramp is positioned beyond an area ofturbulent air adjacent the aircraft.

A28. The retrieval ramp of any of paragraphs A1-A27, wherein theretrieval ramp is configured to be deployed to a plurality of differentheights and distances relative to the aircraft.

A29. The retrieval ramp of any of paragraphs A1-A28, wherein a/the frameis positioned within a/the cargo bay of the aircraft.

A30. The retrieval ramp of any of paragraphs A1-A29, wherein a/the frameis positioned adjacent an aircraft door that provides access to a/thecargo bay of the aircraft.

A31. The retrieval ramp of any of paragraphs A1-A30, wherein a/the frameis coupled to the aircraft.

A32. The retrieval ramp of any of paragraphs A1-A32, wherein a/the frameis selectively and reversibly removable from the aircraft.

A33. The retrieval ramp of any of paragraphs A1-A32, wherein a/the frameis configured to support a/the first ramp portion.

A34. The retrieval ramp of any of paragraphs A1-A33, wherein a/the frameis configured to support a/the ramp adjustment mechanism.

A35. The retrieval ramp of any of paragraphs A1-A34, wherein a/the frameis configured to guide and position a tether that extends from withina/the cargo bay of the aircraft to beyond a/the terminal end of theretrieval ramp, wherein the tether is configured to be coupled to theUAV for transfer of the UAV into and/or out of the aircraft.

A35.1. The retrieval ramp of any of paragraphs A1-A35, wherein a/theframe is configured to guide and position a tether that extends fromwithin a/the cargo bay of the aircraft to beyond the elongate surface ofthe retrieval ramp, wherein the tether is configured to be coupled tothe UAV for transfer of the UAV into and/or out of the aircraft.

A35.2. The retrieval ramp of paragraph A35 or A35.1, wherein the tetheris configured to capture the UAV while the UAV is airborne.

A36. The retrieval ramp of any of paragraphs A1-A35.2, wherein a/theframe is configured to mount a vision system such that the vision systemhas a sufficient field of regard to facilitate capture of the UAV.

A37. The retrieval ramp of any of paragraphs A1-A36, wherein a/the frameis installed in the aircraft non-permanently.

A38. The retrieval ramp of any of paragraphs A1-A37, wherein a/the frameis configured to slide in and out of the aircraft.

A39. The retrieval ramp of any of paragraphs A1-A38, wherein a/the frameis adapted for multiple different types of aircraft.

A40. The retrieval ramp of any of paragraphs A1-A39, wherein a/therestraint structure comprises one or more friction-reducing structuresconfigured to reduce friction between the UAV and at least a portion ofthe restraint structure as the UAV is positioned within the restraintstructure.

A41. The retrieval ramp of paragraph A40, wherein the one or morefriction-reducing structures comprise one or more rollers, wherein eachroller is configured to rotate about its respective longitudinal axis.

A42. The retrieval ramp of paragraph A41, wherein the one or morerollers are configured to rotate when contacted by the UAV as the UAV ispulled into the restraint structure and the UAV is moved with respect tothe one or more rollers, thereby reducing friction between the UAV andthe restraint structure.

A43. The retrieval ramp of any of paragraphs A40-A42, wherein the one ormore friction-reducing structures are configured to guide the UAV intoand/or out of the restraint structure.

A44. The retrieval ramp of any of paragraphs A40-A43, wherein the one ormore friction-reducing structures are positioned within an aft endregion of the restraint structure.

A45. The retrieval ramp of any of paragraphs A1-A44, wherein a/therestraint structure comprises a plurality of spaced-apart arches thatare configured to receive the UAV.

A46. The retrieval ramp of paragraph A45 and of any of paragraphsA40-A44, wherein the one or more friction-reducing structures arepositioned on one or more respective arches of a/the plurality ofarches.

A47. The retrieval ramp of any of paragraphs A1-A46, wherein a/therestraint structure is configured to accommodate a fixed-wing UAV.

A48. The retrieval ramp of any of paragraphs A1-A47, wherein a/therestraint structure is configured to accommodate a foldable-wing UAV.

A49. The retrieval ramp of any of paragraphs A1-A48, wherein a/therestraint structure comprises a drogue-receiver adjacent a fore endregion of the restraint structure.

A50. The retrieval ramp of paragraph A49, wherein the drogue-receiver isconfigured to engage a drogue configured for UAV-capture.

A51. The retrieval ramp of any of paragraphs A49-A50, wherein thedrogue-receiver is coupled to a respective arch of a/the plurality ofarches of the restraint structure.

A52. The retrieval ramp of any of paragraphs A49-A50, wherein thedrogue-receiver is integrally formed with a respective arch of a/theplurality of arches of the restraint structure.

A53. The retrieval ramp of any of paragraphs A49-A52, wherein thedrogue-receiver is basket-like.

A54. The retrieval ramp of any of paragraphs A49-A53, wherein thedrogue-receiver is substantially conical.

A55. The retrieval ramp of any of paragraphs A49-A54, wherein thedrogue-receiver includes an opening through which a/the tether passes.

A56. The retrieval ramp of paragraph A55, wherein the opening isconfigured to prevent passage of the UAV and the drogue there through.

A57. The retrieval ramp of any of paragraphs A49-A56, wherein thedrogue-receiver is configured to be selectively and reversibly movedbetween a transfer configuration, in which the drogue-receiver isconfigured to prevent the UAV from being pulled off the fore end of therestraint structure as the UAV is transferred into the aircraft, to adelivery configuration, in which the drogue-receiver is positioned suchthat the UAV may be transferred from the restraint structure to theaircraft, passing by the fore end region of the restraint structure.

A58. The retrieval ramp of any of paragraphs A49-A57, wherein thedrogue-receiver is configured to rotate with respect to the restraintstructure such that the captured UAV may be removed from the restraintstructure and transferred to the aircraft.

B1. A tether system configured to be used with the retrieval ramp of anyof paragraphs A1-A58, the tether system comprising:

a tether extending from an initial tether end to a terminal tether end,the tether having a length sufficient for retrieving the UAV from an/theairstream outside the aircraft and/or for releasing the UAV into theairstream; and

a capture connector disposed at the terminal tether end of the tether,wherein the capture connector is configured to engage the UAV.

B1.1. The tether system of paragraph B1, further comprising:

a drogue coupled to the terminal tether end of the tether, the droguebeing configured to receive at least a portion of the UAV.

B1.2. The tether system of paragraph B1 or B1.1, wherein the captureconnector is configured to selectively engage a UAV connector of theUAV.

B1.3. The tether system of any of paragraphs B1-B1.2, wherein thecapture connector is configured to be positioned such that it engagesthe UAV outside of turbulence generated by the aircraft, therebycapturing the UAV.

B1.4. The tether system of any of paragraphs B1-B1.3, wherein thecapture connector is configured to be positioned such that it disengagesfrom the UAV outside of turbulence generated by the aircraft, therebyreleasing the UAV.

B1.5. The tether system of any of paragraphs B1-B1.4, wherein the tethersystem is configured to be used with the retrieval ramp to capture theUAV and load the UAV into the aircraft while the aircraft is airborne.

B1.6. The tether system of any of paragraphs B1-B1.5, wherein the tethersystem is configured to be used with the retrieval ramp to transfer theUAV out of the aircraft and release the UAV while the aircraft isairborne.

B2. The tether system of any of paragraphs B1-B1.5, wherein the tethercomprises an elongate, flexible cable.

B3. The tether system of any of paragraphs B1-B2, wherein a/the drogueis funnel-shaped.

B4. The tether system of any of paragraphs B1-B3, wherein a probe of theUAV is configured to be inserted into a/the drogue as the UAV istransferred into and/or out of the aircraft.

B5. The tether system of any of paragraphs B1-B4, wherein the tethersystem is selectively and reversibly moveable between a retractedconfiguration in which the terminal tether end is positioned inside theaircraft, and a capture configuration wherein the terminal tether end ispositioned outside the aircraft.

B6. The tether system of any of paragraphs B5, wherein the tether ispositioned such that it is disposed through a/the restraint structure ofthe retrieval ramp in the capture configuration.

B7. The tether system of any of paragraphs B1-B6, wherein a/the droguecomprises a/the capture connector configured to engage with a UAVconnector positioned on the UAV to be coupled to the UAV.

B7.1. The tether system of paragraph B7, wherein the capture connectoris disposed within the drogue.

B8. The tether system of any of paragraphs B1-B7.1, further comprising atether extension mechanism configured to selectively and reversiblyextend the tether towards a/the capture configuration and retract thetether towards a/the retracted configuration.

B9. The tether system of paragraph B8, wherein the tether extensionmechanism comprises a spool, a reel, a winch, a pulley, and/or aretractable cord reel.

B10. The tether system of any of paragraphs B1-B9, wherein the tethercomprises a stowed portion and an extended portion.

B11. The tether system of paragraph B10, wherein a first length of thestowed portion of the tether is greater in a/the retracted configurationthan a second length of the stowed portion of the tether in a/thecapture configuration.

B12. The tether system of paragraph B10 or B11, wherein a first lengthof the extended portion of the tether is greater in a/the captureconfiguration than a second length of the extended portion of the tetherin a/the retracted configuration.

B13. The tether system of any of paragraphs B10-B12, wherein the stowedportion of the tether is stored within a/the tether extension mechanism.

B13.1. The tether system of any of paragraphs B10-B13, wherein thestowed portion of the tether is stored within a/the cargo bay of theaircraft.

B14. The tether system of any of paragraphs B10-B13.1, wherein thestowed portion of the tether is wrapped around a/the reel, a/the spool,and/or a/the winch of a/the tether extension mechanism.

B15. The tether system of any of paragraphs B10-B14, wherein theextended portion of the tether extends from a/the reel, a/the spool,and/or a/the winch of a/the tether extension mechanism, towards theframe, and extends through a tether guide coupled to the frame.

B15.1. The tether system of any of paragraphs B10-B15, wherein at leasta portion of the extended portion of the tether is positioned withina/the cargo bay of the aircraft, and at least a portion of the extendedportion of the tether is positioned outside the aircraft.

B16. The tether system of any of paragraphs B1-B15.1, wherein theinitial tether end of the tether is engaged with a/the spool, a/thereel, and/or a/the winch of a/the tether extension mechanism.

B17. The tether system of any of paragraphs B1-B16, wherein, in a/thecapture configuration, the terminal tether end is positioned outside theaircraft, in an airstream outside of the aircraft.

B18. The tether system of any of paragraphs B1-B17, wherein, in a/thecapture configuration, the terminal tether end of the tether and thecapture connector are positioned beyond any turbulent air presentadjacent the aircraft.

B18.1. The tether system of any of paragraphs B1-B18, wherein, in a/thecapture configuration, the terminal tether end of the tether and thecapture connector are positioned beyond a/the terminal end of theretrieval ramp.

B19. The tether system of any of paragraphs B1-B18.1, wherein the tethersystem is configured to draw a captured UAV with the capture connector,as the tether is retracted to a/the retracted configuration.

B20. The tether system of any of paragraphs B1-B19, wherein the tethersystem is configured to transfer the UAV out of the aircraft as thetether is extended to the capture configuration.

C1. A UAV, comprising:

a UAV connector configured to engage with the capture connector of thetether system of any of paragraphs B1-B20; and

a probe configured to send and receive wireless data regarding theposition and velocity of the UAV and the aircraft.

C2. The UAV of paragraph C1, wherein the UAV is a fixed-wing UAV.

C3. The UAV of paragraph C1, wherein the UAV has one or more foldablewings.

C4. The UAV of any of paragraphs C1-C3, further comprising one or moresensors configured to facilitate retrieval of the UAV.

D1. A controller for capturing and/or releasing a UAV into or out of anaircraft, while the aircraft is airborne, the controller comprising:

a first sensor configured to measure the relative position and velocitybetween the aircraft and the UAV;

a first processor configured to process data from the first sensor toguide the aircraft and the UAV to a given relative position and velocityfor retrieval; and

a second sensor configured to measure the relative position and velocitybetween a/the UAV connector and a/the capture connector of the tethersystem.

D1.1. The controller of paragraph D1, further comprising:

a second processor configured to process data from the second sensor toguide and engage the UAV connector and the capture connector with eachother, thereby capturing the UAV.

D1.2 The controller of paragraph D1, wherein the first processor isconfigured to process data from the second sensor to guide and engagethe UAV connector and the capture connector with each other, therebycapturing the UAV.

D2. The controller of any of paragraphs D1-D1.2, wherein the controlleris configured to selectively position the retrieval ramp of any ofparagraphs A1-A58 in the stowed configuration, the extendedconfiguration, and any position or arrangement between the stowedconfiguration and the extended configuration.

D2.1. The controller of paragraph D2, wherein the controller isconfigured to position the retrieval ramp in response to measuredrelative positions and velocities of the aircraft and the UAV.

D3. The controller of any of paragraphs D1-D2.1, wherein the controlleris configured to position the tether system of any of paragraphs B1-B20in the retracted configuration, the capture configuration, and anyposition or arrangement between the retracted configuration and thecapture configuration.

D3.1. The controller of paragraph D3, wherein the controller isconfigured to position the tether system in response to measuredrelative positions and velocities of the aircraft and the UAV.

D4. The controller of any of paragraphs D1-D3.1, wherein the controlleris configured for autonomous or semi-autonomous retrieval and/or releaseof one or more airborne UAVs.

D5. The controller of any of paragraphs D1-D4, wherein the first sensorcomprises a GPS system.

D6. The controller of any of paragraphs D1-D5, wherein the second sensorcomprises a LIDAR system.

D7. The controller of any of paragraphs D1-D6, wherein the controller isconfigured to compensate for turbulence near the aircraft.

D8. The controller of any of paragraphs D1-D7, wherein the controller isconfigured to position a/the retrieval ramp, a/the tether system, a/thecapture connector, and/or a/the drogue to avoid turbulence near theaircraft while the UAV is being coupled to a/the capture connector andsecured within a/the restraint structure of the retrieval ramp.

D8.1. The controller of any of paragraphs D1-D8, wherein the controlleris configured to position a/the retrieval ramp and a/the tether systemsuch that a/the capture connector is positioned to avoid turbulence nearthe aircraft while the UAV is being coupled to the capture connector andsecured within a/the restraint structure of the retrieval ramp.

D8.2. The controller of any of paragraphs D1-D8.1, wherein thecontroller is configured to position a/the retrieval ramp and a/thetether system such that a/the capture connector is positioned to avoidturbulence near the aircraft while the UAV is being released from a/thecapture connector into an/the airstream outside the aircraft.

D9. The controller of any of paragraphs D1-D8.2, wherein the controlleris configured to generate and execute instructions that, when executed,cause the first processor to generate navigation control signals fordirecting the UAV to a relative position and velocity based on sensorinformation from the first sensor.

D10. The controller of any of paragraphs D1-D9, wherein the controlleris configured to generate and execute instructions that, when executed,cause the first processor and/or a/the second processor to generatenavigation control signals for directing the UAV to a relative positionand velocity based on sensor information from the second sensor so thatthe UAV connector and the capture connector are engaged with oneanother.

E1. An aircraft comprising the retrieval ramp of any of paragraphsA1-A58, the tether system of any of paragraphs B1-B20, the UAV of any ofparagraphs C1-C4, and/or the controller of any of paragraphs D1-D10,wherein the aircraft is configured to capture and/or release a UAV whilethe aircraft is airborne.

E2. The aircraft of paragraph E1, wherein the aircraft is a carrieraircraft.

E3. The aircraft of paragraph E1, wherein the aircraft is a cargoaircraft.

E4. The aircraft of any of paragraphs E1-E3, further comprising one ormore sensors configured to facilitate capture and/or release of the UAV.

F1. A system for capturing a UAV and loading the UAV into an aircraftwhile the aircraft is airborne, the system comprising:

a retrieval ramp configured to be selectively and reversibly movedbetween a stowed configuration in which the retrieval ramp is containedwithin the aircraft, and an extended configuration, in which at least aportion of the retrieval ramp is positioned outside of the aircraft; and

a tether system configured to be used with the retrieval ramp to capturethe UAV and load the UAV into the aircraft while the aircraft isairborne.

F1.1. The system of paragraph F1, wherein the retrieval ramp is theretrieval ramp of any of paragraphs A1-A58.

F1.2. The system of paragraph F1 or F1.1, wherein the tether system isthe tether system of any of paragraphs B1-B20.

F1.3. The system of any of paragraphs F1-F1.2, further comprising acontroller.

F1.4. The system of paragraph F3, wherein the controller is thecontroller of any of paragraphs D1-D10.

F1.5. The system of any of paragraphs F1-F1.4, wherein, in the extendedconfiguration, at least a portion of the retrieval ramp is positionedbeyond an area of turbulent air adjacent the aircraft.

F1.6. The system of any of paragraphs F1-F1.5, wherein the tether systemincludes a tether that is extendible from near a/the terminal end of theretrieval ramp to a position within a/the airstream around the aircraft.

F1.7. The system of any of paragraphs F1-F1.6, further comprising a/thecapture connector disposed at a/the terminal end of the retrieval ramp,wherein the capture connector is configured to engage a/the UAVconnector of the UAV.

F1.8. The system of paragraph F1.7, wherein the system is configured totransfer the UAV into the aircraft as the tether is retracted towardsthe retracted configuration, once the UAV is engaged with the captureconnector.

F1.9. The system of any of paragraphs F1-F1.8, wherein the system isconfigured to transfer the UAV out of the aircraft and release the UAVinto an airstream outside of the aircraft while the aircraft isairborne.

F2. The system of any of paragraphs F1-F1.9, further comprising theaircraft.

F2.1. The system of any of paragraphs F1-F2, wherein the system is atleast partially contained within the aircraft.

F2.2. The system of any of paragraphs F1-F2.1, wherein the system isconfigured to be installed such that it is at least partially positionedwithin the aircraft.

F3. The system of any of paragraphs F1-F2.2, further comprising the UAV.

F4. The system of paragraph F3, wherein the UAV comprises a plurality ofUAVs.

F5. The system of any of paragraphs F1-F4, wherein the system isconfigured to capture a plurality of respective airborne UAVs.

F5.1. The system of any of paragraphs F1-F5, wherein the system isconfigured to release a plurality of respective stored UAVs bytransferring each respective stored UAV out of the aircraft while theaircraft is airborne.

F6. The system of any of paragraphs F1-F5.1, wherein the system isconfigured for use in a plurality of different types and/or sizes ofaircraft.

F7. The system of any of paragraphs F1-F6, wherein the system isselectively and reversibly removable from the aircraft.

F8. The system of any of paragraphs F1-F7, wherein the system isconfigured to slide into a cargo bay of the aircraft.

F9. The system of any of paragraphs F1-F8, wherein the system isconfigured to capture and/or release the UAV in a location where the UAVavoids turbulence generated by the aircraft while the UAV is beingengaged with or disengaged from a/the capture connector.

F10. The system of any of paragraphs F1-F9, wherein the system isconfigured to position the terminal end of the retrieval ramp beyondturbulence generated by the aircraft while the UAV is being captured orreleased.

F11. The system of any of paragraphs F1-F10, wherein the system isconfigured to be selectively and reversibly moved from a receivingconfiguration in which the system is configured to load a previouslycaptured UAV into the aircraft, to a retrieval configuration in whichthe system is configured to capture an airborne UAV from a positionoutside of the aircraft.

F12. The system of paragraph F11, wherein, in the receivingconfiguration, the tether system is at least partially retracted towardsa/the retracted configuration, the retrieval ramp is at least partiallymoved towards a/the stowed configuration, and/or a/the drogue-receiveris at least partially moved towards the delivery configuration.

F13. The system of paragraph F11 or F12, wherein, in the receivingconfiguration, the system is configured to be contained within theaircraft, such that a cargo bay door may be closed.

F14. The system of any of paragraphs F11-F13, wherein, in the retrievalconfiguration, the tether system is at least partially extended towardsa/the capture configuration, the retrieval ramp is at least partiallymoved towards a/the extended configuration, and/or a/the drogue-receiveris at least partially moved towards the transfer configuration.

F14.1. The system of any of paragraphs F11-F14, wherein, in theretrieval configuration, a/the tether of the tether system extendsbeyond a/the elongate surface of the retrieval ramp.

F15. The system of any of paragraphs F1-F14.1, further comprising atransfer jack configured to transfer a captured UAV from the retrievalramp to a UAV storage structure contained within the aircraft.

F15.1. The system of paragraph F1-F15, wherein the transfer jack isconfigured to transfer a stored UAV from the UAV storage structure tothe retrieval ramp.

F16. The system of paragraph F15 or F15.1, wherein the transfer jack isconfigured to selectively and reversibly raise and lower a respectiveUAV positioned on the transfer jack.

F17. The system of any of paragraphs F15-F16, wherein the transfer jackis configured to selectively and reversibly translate a respective UAVpositioned on the transfer jack, such that the UAV is moved away fromthe retrieval ramp and towards the UAV storage structure, or vice versa.

F18. The system of any of paragraphs F15-F17, wherein the transfer jackis configured to deposit the captured UAV in the UAV storage structure.

F19. The system of any of paragraphs F1-F18, further comprising a/theUAV storage structure for receiving and storing one or more UAVscaptured by the system.

F20. The system of paragraph F19, wherein the UAV storage structurecomprises a plurality of storage cells.

F21. The system of paragraph F19 or F20, wherein the UAV storagestructure is separated from the frame by a distance that is equal to orgreater than the length of the captured UAV.

F22. The system of any of paragraphs F1-F21, wherein the system isconfigured to recharge, refuel, and/or reconfigure one or more capturedUAVs captured by the system.

F23. The system of any of paragraphs F1-F22, wherein the system isconfigured to redeploy one or more UAVs captured by the system.

F24. The system of any of paragraphs F1-F23, further comprising acarriage that is configured to longitudinally slide with respect to theelongate surface of the retrieval ramp.

F25. The system of any of paragraphs F1-F24, further comprising a/thecarriage that is configured to longitudinally slide with respect toa/the first ramp portion, a/the second ramp portion, and/or a/therestraint structure.

F26. The system of any of paragraphs F24-F25, wherein the retrieval rampis configured such that as the restraint structure is moved with respectto the elongate surface of the retrieval ramp, the carriage is movedwith respect to the elongate surface of the retrieval ramp as well.

F27. The system of any of paragraphs F24-F26, wherein the retrieval rampis configured such that as the restraint structure is moved with respectto a/the first ramp portion and a/the second ramp portion, the carriageis moved with respect to the first ramp portion and the second rampportion as well.

F28. The system of any of paragraphs F24-F27, wherein the carriage isconfigured such that at least a portion of the carriage is positioned toextend beyond the elongate surface of the retrieval ramp during captureof the UAV.

F29. The system of any of paragraphs F24-F28, wherein the carriage isconfigured such that at least a portion of the carriage is positioned toextend beyond an/the aft end region of the restraint structure duringcapture and/or release of the UAV.

F30. The system of any of paragraphs F24-F29, wherein the carriage isconfigured to provide support for a captured UAV as the captured UAV isbeing transported into the aircraft, such that the captured UAV ispositioned between the carriage and the restraint structure duringtransfer.

F31. The system of any of paragraphs F24-F30, wherein the carriage isconfigured to move with the UAV as the UAV is pulled into and/ortransferred out of the aircraft.

F32. The system of any of paragraphs F1-F31, further comprising aplurality of carriages, wherein each carriage is configured to be storedin a/the storage structure on the aircraft until use, wherein duringuse, the carriage is positioned on the retrieval ramp and moved alongwith a/the restraint structure with respect to the elongate surface ofthe retrieval ramp, to a position for capturing and/or releasing thenext UAV.

F33. The system of paragraph F32, wherein the system comprises arespective carriage for each respective UAV the system is configured tocapture and/or store.

F34. The system of any of paragraphs F1-F33, wherein the system ispalletized.

G1. A method for capturing and loading a UAV into an aircraft while theaircraft is airborne, the method comprising:

approaching the UAV with the aircraft;

lowering a retrieval ramp from the aircraft towards an extendedconfiguration;

extending a tether towards a capture configuration, the tether having acapture connector coupled to a terminal tether end of the tether,wherein, in the capture configuration, the capture connector ispositioned such that it is configured to engage with a UAV connectorcoupled to the UAV;

capturing the UAV by engaging the capture connector with the UAVconnector coupled to the UAV; and

moving the UAV into the aircraft via the tether and the retrieval ramp.

G1.1. The method of paragraph G1, further comprising moving the UAV intoa restraint structure of the retrieval ramp, and wherein the moving theUAV into the aircraft comprises transferring the restraint structure andthe UAV along the retrieval ramp and into the aircraft.

G1.2. The method of paragraph G1 or G1.1, further comprising:

measuring relative positions and velocities of the aircraft and the UAV;and

positioning the aircraft based on the measured relative positions andvelocities.

G1.3. The method of any of paragraphs G1-G1.2, wherein the transferringthe restraint structure and the UAV into the aircraft comprises:

raising the retrieval ramp from the extended configuration towards astowed configuration; and

retracting the tether towards a retracted configuration.

G2. The method of any of paragraphs G1-G1.3, further comprisingdisengaging the capture connector from the UAV connector.

G3. The method of any of paragraphs G1-G2, further comprising moving adrogue-receiver of the restraint structure from a transfer configurationto a delivery configuration, wherein, in the transfer configuration, thedrogue-receiver is configured to retain a drogue and the UAV within therestraint structure, and wherein, in the delivery configuration, thedrogue-receiver is moved to allow passage of the drogue and the UAVthrough the restraint structure.

G4. The method of any of paragraphs G1-G3, further comprisingtransferring the UAV from the restraint structure onto a transfer jacklocated within the aircraft.

G5. The method of paragraph G4, wherein the transferring the UAV fromthe restraint structure comprises transferring a carriage along with theUAV, wherein the carriage is positioned such that it supports andunderlies the UAV.

G6. The method of any of paragraphs G1-G5, further comprising moving theUAV to a storage structure within the aircraft.

G7. The method of paragraph G6, wherein the moving the UAV to thestorage structure comprises transferring the UAV from a/the transferjack to the storage structure.

G8. The method of paragraph G6 or G7, wherein the moving the UAV to thestorage structure comprises transferring the UAV and a/the carriage tothe storage structure.

G9. The method of any of paragraphs G1-G8, further comprisingtransferring a second carriage to a/the restraint structure.

G10. The method of paragraph G9, wherein the transferring the secondcarriage to the restraint structure comprises transferring the secondcarriage from a/the storage structure to the restraint structure.

G11. The method of paragraph G9 or G10, wherein the transferring thesecond carriage to the restraint structure comprises transferring thesecond carriage via a/the transfer jack.

G12. The method of any of paragraphs G1-G11, further comprising movinga/the drogue-receiver of a/the restraint structure from a/the deliveryconfiguration to a/the transfer configuration.

G13. The method of paragraph G12, wherein the moving the drogue-receivercomprises rotating the drogue-receiver with respect to the restraintstructure.

G14. The method of any of paragraphs G1-G13, further comprising:

re-lowering the retrieval ramp from the aircraft to the extendedconfiguration;

re-extending the tether towards the capture configuration;

capturing a second UAV by engaging the capture connector with a secondUAV connector coupled to the second UAV;

moving the second UAV into the restraint structure coupled to theretrieval ramp;

transferring the restraint structure and the second UAV along theretrieval ramp and into the aircraft;

raising the retrieval ramp from the extended configuration towards thestowed configuration; and

retracting the tether towards the retracted configuration.

G15. The method of any of paragraphs G1-G14, wherein the capturing theUAV comprises capturing a plurality of respective UAVs, one afteranother.

G16. The method of any of paragraphs G1-G15, further comprisingrefueling one or more UAVs on the aircraft.

G17. The method of any of paragraphs G1-G16, further comprisingrecharging one or more UAVs on the aircraft.

G18. The method of any of paragraphs G1-G17, further comprisingreconfiguring one or more UAVs on the aircraft.

G19. The method of any of paragraphs G1-G18, further comprisinglaunching a respective UAV from the aircraft.

G20. The method of any of paragraphs G1-G19, further comprisinglaunching a respective UAV from a ground location.

G21. The method of any of paragraphs G1-G20, further comprisinglaunching a respective UAV from a vessel positioned within a body ofwater.

G22. The method of any of paragraphs G1-G21, further comprising openinga cargo bay door of the aircraft.

G23. The method of any of paragraphs G1-G22, further comprising closinga cargo bay door of the aircraft.

G24. The method of any of paragraphs G1-G23, further comprisinginstalling the system of any of paragraphs F1-F34 in the aircraft.

G25. The method of any of paragraphs G1-G24, further comprising removingthe system of any of paragraphs F1-F34 from the aircraft.

G26. The method of any of paragraphs G1-G25, wherein the retracting thetether towards the retracted configuration comprises reeling,retracting, spooling, and/or coiling the tether around a reel, a winch,a spool, and/or a wheel.

G27. The method of any of paragraphs G1-G26, further comprisingadjusting a ramp angle of the retrieval ramp using a ramp adjustmentmechanism, based on the measured relative locations and velocities ofthe aircraft and the UAV.

G28. The method of any of paragraphs G1-G27, wherein the measuring therelative positions and velocities of the UAV and the aircraft comprisesmeasuring with a first sensor, and wherein the positioning the aircraftcomprises processing the measured relative positions and velocitiesusing a first processor and generating instructions to position theaircraft and the retrieval ramp.

G29. The method of any of paragraphs G1-G28, further comprisingtranslating a/the restraint structure and a/the carriage along theretrieval ramp, until the restraint structure and the carriage arepositioned adjacent a/the terminal end of the retrieval ramp.

G30. The method of paragraph G29, wherein the translating the restraintstructure and the carriage along the retrieval ramp comprises moving therestraint structure and the carriage using a restraint transportmechanism.

G31. The method of any of paragraphs G1-G30, wherein the retrieval rampis the retrieval ramp of any of paragraphs A1-A58.

G32. The method of any of paragraphs G1-G31, wherein the lowering theretrieval ramp comprises lowering the retrieval ramp such that a/theterminal end of the retrieval ramp is positioned in an airstream behindthe aircraft.

G33. The method of any of paragraphs G1-G32, wherein the extending thetether comprises extending the tether such that the capture connector ispositioned beyond turbulence generated by the aircraft while the captureconnector is being engaged with the UAV.

G34. The method of any of paragraphs G1-G33, wherein the capturing theUAV is performed in a location that avoids turbulence generated by theaircraft.

G35. The method of any of paragraphs G1-G34, wherein the positioning theaircraft based on the measured relative positions and velocities of theaircraft and the UAV comprises compensating for turbulence adjacent theaircraft.

G36. The method of any of paragraphs G1-G35, wherein the extending thetether and the retracting the tether are performed using a tetherextension mechanism.

G37. The method of any of paragraphs G1-G36, wherein the capturing theUAV comprises securing the UAV in six degrees of freedom within a/therestraint structure.

G38. The method of any of paragraphs G1-G37, wherein one or more methodsteps are automated.

G39. The method of any of paragraphs G1-G38, wherein one or more methodsteps are performed by an operator on the aircraft.

G40. The method of any of paragraphs G1-G39, wherein the capturing theUAV by engaging the capture connector with the UAV connector coupled tothe UAV comprises measuring relative positions of the capture connectorand the UAV connector with a second sensor.

G41. The method of any of paragraphs G1-G40, wherein the positioning theaircraft comprises processing the measured relative positions usinga/the first processor and generating navigation instructions to guidethe aircraft and the UAV such that the capture connector and the UAVconnector engage.

G42. The method of any of paragraphs G1-G40, wherein the positioning theaircraft comprises processing the measured relative positions using asecond processor and generating navigation instructions to guide theaircraft and the UAV such that the capture connector and the UAVconnector engage.

H1. Use of the aircraft of any of paragraphs E1-E4 to capture and load aUAV into the aircraft, while the aircraft is airborne.

I1. Use of the system of any of paragraphs F1-F34 to capture and load aUAV into an aircraft, while the aircraft is airborne.

J1. Use of the system of any of paragraphs F1-F32 to transfer a UAV outof an aircraft and release the UAV into an airstream outside theaircraft, while the aircraft is airborne.

K1. Use of the aircraft of any of paragraphs E1-E4 to transfer a UAV outof the aircraft and release the UAV into an airstream outside of theaircraft, while the aircraft is airborne.

L1. A method for transferring a UAV out of an aircraft while theaircraft is airborne and releasing the UAV into an airstream outside ofthe aircraft, the method comprising:

lowering a retrieval ramp from the aircraft towards an extendedconfiguration;

extending a tether towards a capture configuration, the tether having acapture connector coupled to a terminal tether end of the tether,wherein, in the capture configuration, the capture connector ispositioned such that it is configured to engage with a UAV connectorcoupled to the UAV;

moving the UAV out of the aircraft via the tether and the retrievalramp; and

releasing the UAV by disengaging the capture connector from the UAVconnector coupled to the UAV.

L2. The method of paragraph L1, further comprising moving the UAV into arestraint structure of the retrieval ramp, and wherein the moving theUAV into the aircraft comprises transferring the restraint structure andthe UAV along the retrieval ramp and out of the aircraft.

L3. The method of any of paragraphs L1-L2, further comprisingtransferring the UAV to the restraint structure from a transfer jacklocated within the aircraft.

L4. The method of paragraph L3, wherein the transferring the UAV to therestraint structure comprises transferring a carriage along with theUAV, wherein the carriage is positioned such that it supports andunderlies the UAV.

L5. The method of any of paragraphs L3-L4, wherein the transferring theUAV to the restraint structure comprises moving the UAV from a storagestructure within the aircraft.

L6. The method of any of paragraphs L1-L5, further comprising:

re-lowering the retrieval ramp from the aircraft to the extendedconfiguration;

re-extending the tether towards the capture configuration;

moving a second UAV into the restraint structure coupled to theretrieval ramp;

transferring the restraint structure and the second UAV along theretrieval ramp and out of the aircraft;

releasing the second UAV by disengaging the capture connector from asecond UAV connector coupled to the second UAV;

raising the retrieval ramp from the extended configuration towards thestowed configuration; and

retracting the tether towards the retracted configuration.

L7. The method of any of paragraphs L1-L6, wherein the releasing the UAVcomprises releasing a plurality of respective UAVs, one after another.

L8. The method of any of paragraphs L1-L7, further comprising refueling,recharging, and/or reconfiguring one or more UAVs on the aircraft.

L9. The method of any of paragraphs L1-L8, wherein the releasing the UAVis performed in a location that avoids turbulence generated by theaircraft.

As used herein, a controller (e.g., controller 16) may be any suitabledevice or devices that are configured to perform the functions of thecontroller discussed herein. For example, the controller may include oneor more of an electronic controller, a dedicated controller, aspecial-purpose controller, a personal computer, a special-purposecomputer, a display device, a logic device, a memory device, and/or amemory device having computer readable media suitable for storingcomputer-executable instructions for implementing aspects of systemsand/or methods according to the present disclosure.

As used herein, the terms “selective” and “selectively,” when modifyingan action, movement, configuration, or other activity of one or morecomponents or characteristics of an apparatus, mean that the specificaction, movement, configuration, or other activity is a direct orindirect result of user manipulation of an aspect of, or one or morecomponents of, the apparatus.

As used herein, the terms “adapted” and “configured” mean that theelement, component, or other subject matter is designed and/or intendedto perform a given function. Thus, the use of the terms “adapted” and“configured” should not be construed to mean that a given element,component, or other subject matter is simply “capable of” performing agiven function but that the element, component, and/or other subjectmatter is specifically selected, created, implemented, utilized,programmed, and/or designed for the purpose of performing the function.It is also within the scope of the present disclosure that elements,components, and/or other recited subject matter that is recited as beingadapted to perform a particular function may additionally oralternatively be described as being configured to perform that function,and vice versa. Similarly, subject matter that is recited as beingconfigured to perform a particular function may additionally oralternatively be described as being operative to perform that function.

The various disclosed elements of apparatuses and systems and steps ofmethods disclosed herein are not required to all apparatuses, systems,and methods according to the present disclosure, and the presentdisclosure includes all novel and non-obvious combinations andsubcombinations of the various elements and steps disclosed herein.Moreover, one or more of the various elements and steps disclosed hereinmay define independent inventive subject matter that is separate andapart from the whole of a disclosed apparatus, system, or method.Accordingly, such inventive subject matter is not required to beassociated with the specific apparatuses, systems, and methods that areexpressly disclosed herein, and such inventive subject matter may findutility in apparatuses, systems, and/or methods that are not expresslydisclosed herein.

1. A system for capturing a UAV and loading the UAV into an aircraftwhile the aircraft is airborne, the system comprising: a retrieval ramphaving an elongate surface extending from a first end of the retrievalramp to a terminal end of the retrieval ramp, wherein the retrieval rampis configured to be selectively and reversibly moved between a stowedconfiguration in which the retrieval ramp is contained within theaircraft, and an extended configuration, in which the terminal end ofthe retrieval ramp is positioned outside of the aircraft and outside ofturbulence generated by the aircraft for capture of the UAV; a tethersystem having a tether extending from an initial tether end to aterminal tether end, wherein the tether system is selectively andreversibly moveable between a retracted configuration in which theterminal tether end is positioned inside the aircraft, and a captureconfiguration wherein the terminal tether end is positioned outside theaircraft, beyond the terminal end of the retrieval ramp; and a captureconnector coupled to the terminal tether end of the tether, wherein thecapture connector is configured to engage the UAV outside of turbulencegenerated by the aircraft, and wherein the system is configured to movethe UAV into the aircraft as the tether is retracted towards theretracted configuration, once the UAV is engaged with the captureconnector.
 2. The system according to claim 1, wherein the retrievalramp further comprises a restraint structure configured to at leastpartially secure the UAV with respect to the elongate surface aftercapture of the UAV and while the UAV is moved towards the aircraft andthrough turbulence generated by the aircraft, wherein the restraintstructure is configured to be selectively and reversibly moved withrespect to the elongate surface of the retrieval ramp.
 3. The systemaccording to claim 2, wherein the restraint structure comprises one ormore friction-reducing structures configured to reduce friction betweenthe UAV and at least a portion of the restraint structure as the UAV ispositioned within the restraint structure, wherein the one or morefriction-reducing structures are configured to rotate when contacted bythe UAV as the UAV is pulled into the restraint structure and the UAV ismoved with respect to the one or more friction-reducing structures,thereby reducing friction between the UAV and the restraint structure.4. The system according to claim 2, wherein the system further comprisesa plurality of carriages, wherein each respective carriage is configuredto longitudinally slide with respect to the elongate surface of theretrieval ramp, wherein each respective carriage is configured toprovide support for a respective UAV during transfer of the respectiveUAV into the aircraft, such that the respective UAV is positionedbetween the carriage and the restraint structure of the retrieval ramponce the respective UAV is captured.
 5. The system according to claim 4,wherein each respective carriage of the plurality of carriages isconfigured to be stored in a storage structure on the aircraft untiluse, wherein during use, the respective carriage is positioned on theelongate surface of the retrieval ramp and moved along with therestraint structure, with respect to the elongate surface of theretrieval ramp, to a position for capturing the next UAV, and whereinthe respective carriage is configured to be stored in the storagestructure with the captured UAV after capturing the respective UAV. 6.The system according to claim 5, further comprising a transfer jackconfigured to transfer a respective UAV between the retrieval ramp andthe storage structure.
 7. The system according to claim 2, wherein thetether is positioned such that it is disposed through the restraintstructure of the retrieval ramp, when the tether system is in thecapture configuration.
 8. The system according to claim 2, wherein thetether system further comprises a drogue coupled to the terminal tetherend of the tether, wherein the capture connector is disposed within thedrogue, and wherein the capture connector is configured to engage with aUAV connector positioned on the UAV such that the drogue is configuredto receive at least a portion of the UAV.
 9. The system according toclaim 8, wherein the restraint structure comprises a drogue-receiveradjacent a fore end region of the restraint structure, wherein thedrogue-receiver is configured to engage the drogue of the tether system,wherein the drogue-receiver includes an opening through which the tetherpasses, wherein the opening is configured to prevent passage of the UAVand the drogue there through, and wherein the drogue-receiver isconfigured to be selectively and reversibly moved between a transferconfiguration, in which the drogue-receiver is configured to prevent theUAV from being pulled off the fore end region of the restraint structureas the UAV is transferred into the aircraft, to a deliveryconfiguration, in which the drogue-receiver is positioned such that theUAV may be transferred from the restraint structure into the aircraft,passing by the fore end region of the restraint structure.
 10. Thesystem according to claim 1, wherein the retrieval ramp comprises: afirst ramp portion, the first ramp portion extending from the first endof the retrieval ramp to a second end of the first ramp portion; asecond ramp portion extending from a proximal end of the second rampportion to the terminal end of the retrieval ramp, wherein the secondramp portion is coupled to the first ramp portion adjacent the proximalend of the second ramp portion and the second end of the first rampportion; and a frame positioned within the aircraft, wherein the firstramp portion is coupled to the frame, wherein the frame is configured tomount a vision system such that the vision system has a sufficient fieldof regard to facilitate capture of the UAV, and wherein the frame isconfigured to guide and position the tether of the tether system;wherein the second ramp portion and the first ramp portion arerotationally disposed with respect to one another, such that a rampangle formed between the first ramp portion and the second ramp portionis adjustable, and such that the second ramp portion may be rotated withrespect to the first ramp portion.
 11. The system according to claim 1,wherein the system is configured to transfer a stored UAV out of theaircraft using the retrieval ramp and the tether system, and wherein thesystem is configured to release the UAV outside of the aircraft whilethe aircraft is airborne, by disengaging the capture connector from theUAV connector at a location outside of the aircraft.
 12. The systemaccording to claim 1, wherein the system is selectively and reversiblyremovable from the aircraft.
 13. The system according to claim 1,further comprising a controller configured to selectively position theretrieval ramp in the stowed configuration, the extended configuration,and any position or arrangement between the stowed configuration and theextended configuration, and wherein the controller is configured toposition the tether system in the retracted configuration, the captureconfiguration, and any position or arrangement between the retractedconfiguration and the capture configuration, and wherein the controlleris configured to position the retrieval ramp and the tether system inresponse to measured relative positions and velocities of the aircraftand the UAV.
 14. An aircraft comprising the system according to claim 1,wherein the aircraft is configured to capture the UAV while the UAV andthe aircraft are airborne.
 15. A method for capturing a UAV and loadingthe UAV into an aircraft while the aircraft is airborne, the methodcomprising: approaching the UAV with the aircraft; lowering a retrievalramp from the aircraft towards an extended configuration; extending atether towards a capture configuration, the tether having a captureconnector coupled to a terminal tether end of the tether, wherein thecapture connector is configured to engage the UAV, wherein, in thecapture configuration, the capture connector is positioned beyond aterminal end of the retrieval ramp such that the tether is configured tocapture the UAV outside of turbulence generated by the aircraft;measuring relative positions and velocities of the aircraft and the UAV;positioning the aircraft based on the measured relative positions andvelocities; capturing the UAV by engaging the capture connector with aUAV connector coupled to the UAV; and moving the UAV into the aircraftvia the tether and the retrieval ramp.
 16. The method according to claim15, further comprising: moving the UAV into a restraint structure of theretrieval ramp; transferring the restraint structure and the UAV alongan elongate surface of the retrieval ramp and into the aircraft; raisingthe retrieval ramp from the extended configuration towards a stowedconfiguration; and retracting the tether towards a retractedconfiguration.
 17. The method according to claim 16, further comprisingmoving a drogue-receiver of the restraint structure from a transferconfiguration to a delivery configuration, wherein, in the transferconfiguration, the drogue-receiver is configured to retain the drogueand the UAV within the restraint structure, and wherein, in the deliveryconfiguration, the drogue-receiver is moved to allow passage of thedrogue and the UAV through the restraint structure.
 18. The methodaccording to claim 16, further comprising: transferring the UAV from therestraint structure onto a transfer jack located within the aircraft,wherein the transferring the UAV from the restraint structure comprisestransferring a carriage along with the UAV, wherein the carriage ispositioned such that it supports and underlies the UAV; and moving theUAV and the carriage to a storage structure within the aircraft.
 19. Themethod according to claim 18, further comprising: transferring a secondcarriage from the storage location to the restraint structure. movingthe drogue-receiver of the restraint structure from the deliveryconfiguration to the transfer configuration; re-lowering the retrievalramp from the aircraft to the extended configuration; re-extending thetether towards the capture configuration; capturing a second UAV byengaging the capture connector with a second UAV connector coupled tothe second UAV; moving the second UAV into the restraint structurecoupled to the retrieval ramp; transferring the restraint structure andthe second UAV along the retrieval ramp and into the aircraft; raisingthe retrieval ramp from the extended configuration towards the stowedconfiguration; and retracting the tether towards the retractedconfiguration.
 20. The method according to claim 15, wherein thecapturing the UAV comprises capturing a plurality of respective UAVs,one after another.
 21. A method, comprising: removing the system ofclaim 1 from a first aircraft in which the system is installed; andinstalling the system in a second aircraft, the second aircraft beingdifferent from the first aircraft.